has doing是什么時態(tài)

　　Each nation has its own peculiarities when it comes to doing business.

　　說到做生意，每個民族都有它自己獨有的一些特性。

　　The government has been doing some blue-sky thinking on how to improve school standards.

　　就如何提高學校的水平，政府仍然在作一些漫無邊際的構(gòu)想。

　　Embarrassment has kept me from doing all sorts of things.

　　難為情使得我什么也做不了。