House prices vary from place to place and are usually high _____ there are famous schools.

Do you have any idea what your former boss would say about you? —I don’t know，________.

Do you know David well?——SureWefriends since ten years ago

The scientists all agreed that rules of physics, ______ we are all familiar, govern the world

20．It was four o’clock in the afternoon_____he and his grandpa reached the museum in Guanghan, _____an official warmly received them