填空题


【参考答案】

which
<上一题 目录 下一题>
热门 试题

单项选择题
A．They never occur.B．They are net affected by the force of gravity.C．In still air they would fall to earth.D．In moving air they fall at a speed of thirty-two miles per hour.
A．They never occur.
B．They are net affected by the force of gravity.
C．In still air they would fall to earth.
D．In moving air they fall at a speed of thirty-two miles per hour.
单项选择题
A．They are kept aloft by air currents.B．They combine with other chemicals in the atmosphere.C．Most of them evaporate.D．Their electrical charges draw them away from the eart
A．They are kept aloft by air currents.
B．They combine with other chemicals in the atmosphere.
C．Most of them evaporate.
D．Their electrical charges draw them away from the eart
相关试题