用机械钥匙开关翻开任一层厅门时，手一脱离厅门，厅门应（）。
A、当即关闭
B、原地不动
C、报警
D、继续翻开
参考答案：A
He felt _______ to remind the public to protect the environment.
A．his duty
B．that is his duty
C．it his duty
D．it is his duty
国际储备中的普通提款权是指（）。
A.黄金储备
B.外汇储备
C.SDR
D.在基金组织的储备头寸
