1 . The place        the bridge is supposed to be built should be         the cross-river traffic is the heaviest.

A．which, that	B．at which,where
C．at which,that	D．where, in which

3 . Don’t be sad. The most important thing is _____ we must learn from our mistakes and move on.

A．how

B．that

C．what

D．why

4 . He did not see the film last night. That is _______ he had to help his little sister with her homework.

A．why

B．because

C．that

D．how

5 . Respect is not one-way traffic but mutual, and that might be          we fight back in the trade friction against the USA   .

A．where

B．because

C．why

D．how

6 . Everyone on this planet is different, and that's______   makes it such a beautiful place.

A．When

B．how

C．what

D．why

7 . It is generally believed that communication skills are becoming ________ it takes to be a good doctor.

A．that	B．what
C．whether	D．how

8 . （2018· 北京）This is _________ my father has taught me—to always face difficulties and hope for the best.

A．how	B．which
C．that	D．what

9 . (2015·安徽)A ship in harbor is safe, but that’s not _____________ ships are built for.

A．what	B．whom
C．why	D．when