keep的过去式

　　He kept us at it all day.

　　他让我们不停地干了一天。

　　For reasons of security the door is always kept locked.

　　为了保证安全，门总是锁着的。

　　Dogs must be kept on a lead in the park.

　　狗在公园里必须系着牵狗带。

　　The bills kept coming in, one after another.

　　账单纷至沓来。

　　Next year's collection is still being kept under wraps.

　　明年的时装系列仍在保密之中。