It was so dark in the theatre that I could hardly ________ my friend.
The number of smokers in China ________ decreased in recent years.
The foreigner was talking to the children in the park ______ he was familiar with them.
Frank ______ London by train which ________ at 8:30 next morning.
As you get older, your _______ towards the matter will change.
–Have you finished your experiment report, Jane? --Oh, my god! I’ve _______ forgotten all about that.