The teacher will be backan hour.
A. in B. after C. on
Look! The bird __in the sky.
A. is flying B. flies C. fly
My birds can ___by one of my friends while I'm away.
A. be looking after
B. look after
C. be looked after.
Jack__China__two years.
A.has been in, for
B. has been in, since
C. has come to, for
John knowsa computer.
A. how to use B. how use C. how uses