—I wonder why he has been acting so strangely these days．—Recent pressure at work may ____ his behavior．

In order to know how heavy the elephant was, he wrote down the weight of each stone and then           ____all the weights.

I ______ an old letter while I was searching my drawer.

The job was a great challenge and the bad weather _________ our difficulties．

—We’d like Chinese black tea,please.—Sorry,we don’t __________ Chinese tea.