Soon after the mud-rock flow hit Zhouqu, Gansu Province, many soldiers came to the ______ as many people were trapped underground.

 Those black clouds are a sure _____ that it’s going to rain. 

 There is a _________ of 1000 dollars for the return

 His name is on the _______ of my tongue, but I just couldn’t remember it.

Having a fever is the ______________ of SARS.