—When did you buy this computer? It looks so new.

—I         it for only a couple of days. My sister bought it for me as a birthday present.

A．bought

B．have bought

C．have had

D．had

以下关于车钩三态的说法不正确的是

A.当车钩处于闭锁位置时，钩舌不能绕舌销向外自由转动

B.当车钩处于开锁位置时，钩锁仍然挡住钩舌

C.当钩锁处于开锁位置时，继续提升钩锁销，车钩将处于全开状态