What kind of teachers do you like， John？
I like the teachers _____are friendly to us．（ ）
A．whichB．whoseC．who
which would you like，tea_______ milk？Tea，please．（ ）
A．andB．orC．but
Is tom coming by train？He ______drive his car，I'm not sure．（ ）
A．can'tB．mayC．must
_______ Children's Day，all the children are very happy．（ ）
A．toB．InC．On
What were you doing when I phoned you yesterday evening？
I _______ my homework．（ ）
A．was doingB．have doneC．did
Fifty yuan ________ enough．（ ）
A．isB．amC．are