He comes late sometimes,______?[ ]

The Tibetansin the Himalayas for centuries and have adjusted to the conditionsat________

Stephen Hawking has expressed his opinion ___ humans mightone day be able to make spaceships capable of such speeds that time on boardwould slow down

What kind of job have you ever done before?–Oh, I _________ for an engineering company for three years,

It may not be a great suggestion.But before________is put forward，we’ll make do with it.