Yunnan province in China was attacked by such a terrible drought this early spring ____________few people had experienced before,  ____________ made us worry about global climate changes.

Yunnan province in China was attacked by such a terrible drought this early spring    ________ few people had experienced before, _______ made us worry about global climate changes.

       A. that; that   B. as; which  C. which; it       D. when; as

Yunnan province in China was attacked by such a terrible drought this early spring ____________few people had experienced before,  ____________ made us worry about global climate changes.

1. A.
   that; that
2. B.
   as; which
3. C.
   which; it
4. D.
   when; as

Yunnan province in China was attacked by such a terrible drought this early spring    ________ few people had experienced before, _______ made us worry about global climate changes.

       A. that; that   B. as; which  C. which; it       D. when; as

Yunnan province in China was attacked by such a terrible drought this early spring ____________few people had experienced before,  ____________ made us worry about global climate changes.

       A．that; that   B．as; which  C．which; it   D．when; as