Monkeys in the zoo started to show the flu _____ last Monday and altogether twenty have died up to now．

There seemed to be no human beings in that village, and the only ______ of life was a boat tied to a tree.

These continual _____ in temperature make it impossible to decide what to wear.

You can ask him again if you like , but it won’t make any      —he’ll still say no .

With international ______ and education exchanges increasing every year, the number of Chinese students studying abroad has increased rapidly.