______ it is to have a picnic in the hills on such a nice day!
John promised his doctor he _____ not smoke and he has never smoked ever since.
According to the air traffic rules, you ___ switch off your mobile phone before boarding.
When I was young, I was told that I ______ play with matches
-What sort of house do you want to have? Something big?--Well, it ______ be big--that's not important.
—I can’t find my purse anywhere.—You __ have lost it while shopping.