汽车起重机具有行驶速度高，转移灵活等优点；轮胎起重机具有可吊重行驶的优点。
参考答案：对
Some students even have no idea of they are studying, so they waste much time playing.
A．what
B．when
C．why
D．where
无菌罐有（）个温度探头。
A.4
B.5
C.6
