Sometimes he found _______very hard to fall asleep at night, so he went to see the doctor．

Make sure you’ve got the passports and tickets and _________ before you leave.

–Excuse me, but can you tell me which road I should take to the post office?--______ of the four roads will do.

We had a picnic last term and it was a lot of fun, so let’s have _______ one this month.

--John, when shall we meet again, Thursday or Friday? --___________.I’ll be off to London then.