1 . The nutrients in _____falls into the ocean quickly become available to other living creatures.

A．whatever

B．whichever

C．that

D．wherever

2 . Saving and recycling are long-term projects _______ determination matters a great deal.

A．that

B．which

C．whose

D．where

3 . Is this research center _________ you met some foreign guests last week?

A．that

B．where

C．which

D．in which

4 . We are so sorry for that．We'll try to determine exactly _________ went wrong that evening．

A．where

B．what

C．which

D．how

5 . To improve the quality of our products, we asked for suggestions _____ had used the products.

A．whoever

B．who

C．whichever

D．Which