A clause is a grammatical unit that includes, at minimum, a predicate and an explicit or implied subject, and expresses a proposition. An adverbial clause is a clause that has an adverb-like function in modifying another clause.
1. Adverb Clauses with Time
• He was talking on the phone when I arrived.
• When she called, he had already eaten lunch.
• I washed the dishes when my daughter fell asleep.
• We'll go to lunch when you come to visit.
'When' means 'at that moment, at that time, etc.'. Notice the different tenses used in relationship to the clause beginning with when. It is important to remember that 'when' takes either the simple past OR the present - the dependent clause changes tense in relation to the 'when' clause.
• We will finish before he arrives.
• She (had) left before I telephoned.
' bfore' means 'before that moment'. It is important to remember that 'before' takes either the simple past OR the present.
• We will finish after he comes.
• She ate after I (had) left.
'After' means 'after that moment'. It is important to remember that 'after' takes the present for future events and the past OR past perfect for past events.
• She began cooking while I was finishing my homework.
• As I was finishing my homework, she began cooking.
'While' and 'as' mean 'during that time'. 'While' and 'as' are both usually used with the past continuous because the meaning of 'during that time' which indicates an action in progess.
By the time
• By the time he finished, I had cooked dinner.
• We will have finished our homework by the time they arrive.
'By the time' expresses the idea that one event has been completed before another. It is important to notice the use of the past perfect for past events and future perfect for future events in the main clause. This is because of the idea of something happening up to another point in time.
• We waited until he finished his homework.
• I'll wait till you finish.
'Until' and 'till' express 'up to that time'. We use either the simple present or simple past with 'until' and 'till'. 'Till' is usually only used in spoken English.
• I have played tennis since I was a young boy.
• They have worked here since 1987.
'Since' means 'from that time'. We use the present perfect (continuous) with 'since'. 'Since' can also be used with a specific point in time.
As soon as
• He will let us know as soon as he decides (or as soon as he has decided).
• As soon as I hear from Tom, I will give you a telephone call.
'As soon as' means 'when something happens - immediately afterwards'. 'As soon as' is very similar to 'when' it emphasizes that the event will occur immediately after the other. We usually use the simple present for future events, although present perfect can also be used.
Whenever, every time
• Whenever he comes, we go to have lunch at "Dick's".
• We take a hike every time he visits.
'Whenever' and 'every time' mean 'each time something happens'. We use the simple present (or the simple past in the past) because 'whenever' and 'every time' express habitual action.The first, second, third, fourth etc., next, last time
• The first time I went to New York, I was intimidated by the city.
• I saw Jack the last time I went to San Francisco.
• The second time I played tennis, I began to have fun.
The first, second, third, fourth etc., next, last time means 'that specific time'. We can use these forms to be more specific about which time of a number of times something happened.
2. Adverb Clauses Showing Opposition
Even though, though, although
• Even though it was expensive, he bought the car.
• Though he loves doughnuts, he has given them up for his diet.
• Although he course was difficult, he passed with the highest marks.
Notice how 'though, even though' or 'although' show a situation which is contrary to the main clause to express opposition. Even though, though and although are all synonyms.
• Whereas you have lots of time to do your homework, I have very little time indeed.
• Mary is rich, while I am poor.
'Whereas' and 'while' show clauses in direct opposition to each other. Notice that you should always use a comma with 'whereas' and 'while'.
3. Different Time Expressions
• If we win, we'll go to Kelly's to celebrate!
• She would buy a house, if she had enough money.
'If' clauses express the conditions necessary for the result. If clauses are followed by expected results based on the condition. More information on the correct tense usage for the conditionals• Even if she saves a lot, she won't be able to afford that house.
In contrast to sentences with 'if' sentences with 'even if' show a result that is unexpected based on the condition in the 'even if' clause. Example: COMPARE: If she studies hard, she will pass the exam AND Even if she studies hard, she won't pass the exam.
Whether or not
• They won't be able to come whether or not they have enough money.
• Whether they have money or not, they won't be able to come.
'Whether or not' expresses the idea that neither one condition or another matters; the result will be the same. Notice the possibility of inversion (Whether they have money or not) with 'whether or not'.
• Unless she hurries up, we won't arrive in time.
• We won't go unless he arrives soon.
'Unless' expresses the idea of 'if not' Example: Unless she hurries up, we won't arrive in time. MEANS THE SAME AS: If she doesn't hurry up, we won't arrive in time. 'Unless' is only used in the first conditional.In case (that), in the event (that)
• In the case you need me, I'll be at Tom's.
• I'll be studying upstairs in the event he calls.
'In case' and 'in the event' usually mean that you don't expect something to happen, but if it does... Both are used primarily for future events.
• We'll give you your bicycle only if you do well on your exams.
• Only if you do well on your exams will we give you your bicycle.
'Only if' means 'only in the case that something happens - and only if'. This form basically means the same as 'if'. However, it does stress the condition for the result. Note that when 'only if' begins the sentence you need to invert the main clause.
4. Adverb Clauses of Cause and Effect
• They received a high mark on their exam because they had studied hard.
• I'm studying hard because I want to pass my exam.
• He works a lot of overtime because his rent is so expensive
Notice how because can be used with a variety of tenses based on the time relationship between the two clauses.
• Since he loves music so much, he decided to go to a conservatory.
• They had to leave early since their train left at 8.30.
'Since' means the same as because. 'Since' tends to be used in more informal spoken English. Important note: "Since" when used as a conjunction is typically used to refer to a period of time, while "because" implies a cause or reason.
As long as
• As long as you have the time, why don't you come for dinner?
'As long as' means the same as because. 'As long as' tends to be used in more informal spoken English.
• As the test is difficult, you had better get some sleep.
'As' means the same as because. 'As' tends to be used in more formal, written English.
• Inasmuch as the students had succesfully completed their exams, their parents rewarded their efforts by giving them a trip to Paris.
'Inasmuch as' means the same as because. 'Inasmuch as' is used in very formal, written English.
Due to the fact that
• We will be staying for an extra week due to the fact that we haven not yet finished.
'Due to the fact that' means the same as because. 'Due to the fact that' is generally used in very formal, written English.