1. because: As he is my friend, I will help him.
2. when: We watched as the plane took off.
1. later in time: After the train left, we went home.
Although or though
1. in spite of the fact that: Although it was after midnight, we did not feel tired.
1. earlier than: I arrived before the stores were open.
1. for the reason that: We had to wait, because we arrived early.
1. for, because: He is happy, for he enjoys his work.
1. on condition that: If she is here, we will see her.
1. for fear that: I watched closely, lest he make a mistake.
Note the use of the Subjunctive Mood in the clause with lest.
Providing or provided (contanto que)
1. on condition that: All will be well, providing you are careful.
1. from a past time: I have been here since the sun rose.
2. as, because: Since you are here, you can help me.
So or so that
1. consequently: It was raining, so we did not go out.
2. in order that: I am saving money so I can buy a bicycle.
Note: When used with the meaning in order that, so is usually followed by that in formal English.
e.g. I am saving money so that I can buy a bicycle.
1. if: Supposing that happens, what will you do?
1. used in comparisons: He is taller than you are.
1. except when, if not: Unless he helps us, we cannot succeed.
Until or till
1. up to the time when: I will wait until I hear from you.
1. because: Whereas this is a public building, it is open to everyone.
2. on the other hand: He is short, whereas you are tall.
1. if: I do not know whether she was invited.
1. at the time when: While it was snowing, we played cards.
2. on the other hand: He is rich, while his friend is poor.
3. although: While I am not an expert, I will do my best.
In addition, the following phrases are often used at the beginning of subordinate clauses.
1. in a similar way: She talks as if she knows everything.
As long as
1. if: As long as we cooperate, we can finish the work easily.
2. while: He has lived there as long as I have known him.
As soon as
1. immediately when: Write to me as soon as you can.
1. in a similar way: It looks as though there will be a storm.
1. in spite of a possibility: I am going out even if it rains.
1. because of a possibility: Take a sweater in case it gets cold.
1. otherwise: Please be careful, or else you may have an accident.
So as to
1. in order to: I hurried so as to be on time.