Itseemsasifthesun_____roundtheearthsinceitrisesintheeastandsetsinthewest.
D
“as if ”“ 似乎，好象”，太阳并不是绕着地球转， 所以后面应该与事实相反的假设， 要用虚拟语气。需要特别指明的是： “如果是一般的客观规律的陈述，则用一般现在时 ”。
Thosepeople_____ageneralunderstandingofthepresentsituation.
_____youunderstandthisrule，you‘llhavenodifficultyindealingwithsuchproblems.
It was not until she had finished all her work_____.