Noise is unpleasant, _____ when you are trying to sleep.
_____ an ad does not lie, it does not mean it is altogether innocent.
She set off at 9 a.m. and ____ the airport an hour later.
If ____ in, viruses can result in illness or even death.
By the 1920s, Howard Carter ____ an explorer.
Three mountains, Meili, Baimang and Haba, _____ are covered with snow, tower over the land.