I really don’t know ______ about it.

–Your mother’s never seen a 3D film at the cinema, has she?--____, but only once.

—— He didn’t catch the train, did he? ——__________, though he was caught in the rain.

It is now 11:30 pm, so there are few people and buses on the street, ____________ ?

--I’m worried about my English. -- ______ harder ________ you will catch up with your classmates.