1. You will want two trees about ten feet apart, from ________to suspend your tent.

   A there         B then            C which             D where

2. That was so serious a matter that I had no choice but ______the police.

   A called in      B calling in         C call in            D to call in

3. Americans eat ________as they actually need every day.

   A twice as much protein             B protein twice as much

   C twice protein as much             D protein as twice much

1. 正確答案：C

例題解析：    介詞+關系代詞+不定式作定語，只有which 是關系代詞。

2. 正確答案：D

   例題解析：Have no choice but 后要帶接to 的不定式，意思是 只能……別無選擇。

3. 正確答案：A      

例題解析：譯文：美洲人每天所食用的蛋白質是他們實際需要的兩倍。倍數(shù)+as+形容詞+as，表示倍數(shù)