根据句意，写出括号内所给单词的适当形式。

小题1:We love our children and our parents love ______(they).

小题2:If giant pandas are in ______(dangerous), they will attack people.

小题3:______(luck), he was not badly hurt in the car accident last month.

小题4:Thousands of ______ (tour) come to the Great Wall every year.

小题5:The places ______(mark) in red are very dangerous.

Her father is a famous writer,      always makes her very proud.

A．that

B．which

C．who

D．what