下列哪一种植物的受精离不开水[ ]
A．水稻
B．卷柏
C．水仙
D．莲
答案：B
My mother is working so that she can have any time for me．
A．hard, hard
B．hardly, hardly
C．hardly; hard
D．hard, hardly
空气中一氧化碳的含量达()时，5分钟使人致死
A、5％～10％
B、0.5％～1％
C、0.05％～0.5％
D、10％～20％
