下列哪项为美国船级社的无人机舱船级符号（）。
A．UMS
B．ACCU
C．AUT
D．MO
参考答案：B
— Excuse me, sir. Is the swimming pool open all day as it used to be?
— _____. only from 6:00p.m to 10:00p.m.[ ]
A．That's right
B．Yes, of course
C．Sorry, I'm not sure
D．Sorry, I'm afraid not
不具有细胞结构的生物是______．
