has doing是什麼時態

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想。

Embarrassment has kept me from doing all sorts of things.

難爲情使得我什麼也做不了。