选词填空完成短文。

well     soft    second     better    may      strongly afraid   sand    stay up     if       times     house

we can't stop an earthquake(地震), but we can do things to make sure they don't destroy(毁坏) whole cities. first, it is not a  idea to build houses along lines where the      of the earth's plates(板块) join together. Second, if you think there__ be an earthquake, it is better to build houses on rocks , not on ___. Third, you must make the houses as       as possible. Weak buildings will fall down in an earthquake, but strong ones may   Scientists are      that one day an even bigger earthquake will hit the part around San Francisco(旧金山) . They call it " the big one ". However, people today are still building more_____  .The population in and around San Francisco is now ten        more than it was in 1906.This means that        there is another earthquake, a great many houses and buildings will be destroyed.