seem常用于由as if/though引導的從句中，如：
a) It seems as if it is going to rain.
b) It seems as though our plan’ll be perfect.
c) It seems as if he knew nothing about that.
d) It seems as if it was/were spring already.
[注]在這種句式中，如從句所敘述的情實現的可能性比較大，從句謂語用陳述語氣
，如a,b兩例；若實現的可能性較小，或根本不可能實現，從句的謂語則用虛擬語氣，如c,d 兩例。