Why are the lights in the teachers’ office still on—There ________ be some teachers working there.

What do you think of the voice of Adele who won 2017 Grammy Awards— Oh, I’ve never heard ________ one.

– When does your plane take off?—– At 3:00 p.m. tomorrow, I’ve just called the airport to ____it.

His face looks familiar(熟悉的) to me. I remember _____him ______ in my hometown.

_ is expected, according to the online survey,is _______ the price of housing will not go up any more