is kept是什么時(shí)態(tài)

　　All our glass and China is kept in the cupboard.

　　我們所有的玻璃器皿和瓷器都放在碗櫥里。

　　For reasons of security the door is always kept locked.

　　為了保證安全，門總是鎖著的。

　　The suspect is being kept under observation.

　　嫌疑人正受到監(jiān)視。

　　A skeleton staff of 20 is being kept on.

　　留下了20名骨干人員。

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

　　明年的時(shí)裝系列仍在保密之中。