问题补充:
There are three sheep on the farm.
A. thousand
B. thousands
C. thousand of
D. thousands of
答案:
A. thousand
B. thousands
(答案→)C. thousand of
D. thousands of
解析:此题考查名词的量。确切数量常用数词+hundred/thousand/million/billion+名词的复数形式;不确切数量常用hundreds/thousands/millions/billions + of+名词的复数形式.