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
网友回答
(答案→)A. were circling
B. circles
C. is circling
D. be circling
解析：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。