Question

I have lost sight of my mom, but I just saw her _____ in front of me.

I have lost sight of my mom, but I just saw her _____ in front of me.

A
were walking

B
to have walked

C
walk

D
walking

Answer 1

句中子I have lost sight of my mom,but I just saw her__in front of me.意思为“我看不见我的妈妈，但是我之前看见过她……”。短语lost sight of意思是“看不见，不容忽视”，in front of 意思是“在……之前，在……前面”。因此，这里应该是选择D。因为see sb. doing sth.，所以，这里应该是用V-ing形式

Answer 2

D，意思是我刚还看见我母亲正在我面前走。
see sb.doing 看见某人正在做某事
see sb.do 看见某人做某事(全过程)
see sb.to do 看见某人去做某事

Answer 3

这题目意思是我弄丢了妈妈，但我刚才看见她走在我的前面。题目出现just，表示看到的动作已完成， 考察的是see sb do sth。因此答案选C。