1. An employment survey revealed that demand for high-level executives _______
decreased unexpectedly this year.
答案是has 但我挑了have 请问这种has have到底如何判别 我常常搞不懂QQ
2. The tuition of a public university is usually much lower than (that of) a p
rivate university.
括号中为什么不能用 which of 呢？
3. Because of the Eskimos’ constant exposure to cold weather, they have long
recognized ______.
空格是 the body’s need for fat
为什么不能选 how fat the body needs.
4. Americans have come to fear the West Nile virus, (because it is transmitted
) by the common mosquito.
为什么括号中为不能选being transmitted呢？
这种句子被动式且主词相同不是可以省略主词并把be动词变being吗？
先谢谢各位了QQ