(1) Air and water are indispensable to me.
(2) She likes going out with friends or playing outdoor games.
(3) Most workers have a good income, so they look very happy.
(4) He said that he did not want to go .
(5) Many things have happened since I last saw him.
(6) You may come if you want to.
I studied hard until 12 o'clock last night.
He didn't go to bed until his mother came back.
I have studied English since 1990.
I had learned 25 English songs by the end of last term.