Great changes have taken place around theworld. Nobody can tell _____ in 20 years.

We travelled together as far as Chicago, _______ we parted.

It was at four o’clock in the afternoon____ he and his grandpa reached the museum in Guanghan

Have you seen your aunt lately? —Yes, in fact I saw her yesterday．I_________ her for several months

_______nearly all behavior is learned behavior is a basic assumption ________has been put forward by the social scientists.