Which girl is your sister? —- The girl ___________is wearing dark glasses.

I took the wrong train ______, I didn’t even know it until half an hour later. [ ]

He is the only student______ I’ve ever met ______ could answer this question .

Why didn’t David ________his friend’s invitation to the picnic?—Because he had to prepare for the exam.

What’s your mother__________ now？ —She’s __________ our house.