什么是核电厂的严重事故？
参考答案：
即堆芯严重损坏的事故，就是超出设计基准的事故。
—What happened to Mike?
—He had a stomachache. He began to work _______ having breakfast this morning.
A．with
B．of
C．from
D．without
蓄电池内部电解液中含有过量的铜.铁等金属杂质，可能会造成蓄电池极板硫化。
