The pen I ________ I ________ is on my desk,right under my nose.
问题描述：
The pen I ________ I ________ is on my desk,right under my nose.
A.think; lost B.thought; had lost
C.think; had lost D.thought; have lost
为什么D不行啊
答
B
thought是过去时,在过去时为主句的情况下,从句如果是完成时要用过去完成时
因为主句的时态决定从句的时态,主句是过去时,所以从句也应该是过去时\,所以要用过去完成时
但是有一种情况例外,就是从句是不可改变的客观事实,比如:Yesterday,our teacher told us that the earth turns around the sun 昨天我们老师告诉我们地球绕着太阳转,因为这是客观事实,是不能改变的所以要用一般现在时