问题
选择题
The sun rises in the east and sets in the west，so it seems as if the sun__________round the earth.
A．were circling
B．circles
C．is circling
D．be circling
答案
A
as if引导的从句要求用虚拟语气，动词要用过去时（be动词用were）或would(could等)+动词原形，本句话中指的是当时的情况，所以要用过去式，故A是正确答案。