I often thought of my childhood,____ I lived on a farm.
A、who
B、when
C、where
D、which
"Lookwhatyou'vedone!You______morecareful."
A、hadtobe
B、shouldbe
C、shouldhavebeen
D、mustbe
The city government has determined to get _____ with people who try to escape payingtaxes.
A、rough
B、tough
C、rigid
D、bold
Youcantakeanyseat____isfree.
A、inwhich
B、that
C、where
D、which
The time has come _____ we make extensive use of nuclear energy.
A、When
B、while
C、as
D、since