白及的功效是（）。
A.收敛止血，解毒
B.收敛止血，止痢
C.收敛止血，消肿生肌
D.凉血养阴，解毒
E.凉血止血，消肿生肌
参考答案：C
At the end of the meeting, it was announced that an agreement ________.
A．has been reached
B．had been reached
C．has reached
D．had reached
离心泵启动后，在泵出口阀关闭的情况下，泵连续工作的时间一般不应该超过（）分钟。
A、1
B、2
C、5
D、10
