宋代词人辛弃疾在一首词中写道“稻花香里说丰年，听取蛙声一片”，夏季青蛙高声鸣叫的行为是 [ ]
A．贮食行为
B．繁殖行为
C．攻击行为
D．防御行为
B
—Did you ________ any people?
—Yes, there _ _lots of people there. [ ]
A. saw; are
B. saw; were
C. see; are
D. see; were
如果左、右手电极反接记录心电图。
记录的Ⅲ导联心电图相当于实际心电图的（）。
A.Ⅱ导联
B.Ⅰ导联
C.aVR导联
D.aVL导联
E.aVF导联
