焊接当中可燃容器发生爆炸属于()。
A、化学爆炸
B、物理爆炸
C、核爆炸
参考答案:A
Jamaican Usain Bolt was reported ______the world record of 100m in 9.69 seconds, thus winning his first gold medal.
A.breaking
B.having broken
C.to be broken
D.to have broken
铁路运输是()陆上运输方式;水路运输的最大优点是()。