A warm thought suddenly came to me _____ I might use the pocket money to buy some flowers for my mother's birtday.
A. when
B. that
C. how
D. what
We haven’t settled the question of _____ it is necessary for him to study abroad.
A. which
B. that
C. what
D. whether
You can only be sure of ______ you have at present; you cannot be sure of something ____ you might.
A. That; what
B. what; /
C. which; that
D. /; that
Having checked the doors were closed, and _____ all the lights were off, the boy opened the door to his bedroom.
A. why
B. that
C. when
D. where