这句话中hit的具体意思

这句话中hit的具体意思
If an earthquake hits when they're in a classroom, children learn to get under their desks ,head first,and to hold on to the legs of the desk until the quake is over.请把这句话翻译一下,并说出本句中“hit”的具体意思, 不要笼统地翻译成“发生”哦~