Fill in each blank with one of the conjunctions "and/ or/ but/ so/ although

III. Fill in each blank with one of the conjunctions "and/ or/ but/ so/ although”

1.He helps his friends a lot ________ he is very busy.
2.Lan sings very well __________ she cannot sing in front of many people.
3.My new classmate is quite friendly ___________sociable.

IV. Rewrite the following sentences

1. This is the first time I have joined such an exciting party.=> I haven't _______________________________________________________________
2. I haven't heard from her for many years.=> The last _______________________________________________________________