荧光灯逆变器是将（）电转化为交流电，从而点燃（）。
参考答案：直流电；荧光灯
如图所示是用温度计测量液体温度的示意图，其中温度计使用正确的是（ ）
A．
B．
C．
D．
From time to time a crocodile has snatched someone _______ he or she is even aware that the crocodile is there.
A．when
B．until
C．since
D．before
