Do you know how many bridges _____ over the Yangtze River in Jiangsu Province by the end of last year—Sorry. I have little knowledge about it.

There is _____pollution and ____fishes in the river now than 20 years ago.

Brother! You’ve eaten my apple Why一Because I very hungry.

_______ will your father come back from Beijing —In two days.

_____ the calculation is right, scientists can never be sure that they have included all variables and modeled them accurately