单项选择题
Having been familiar with his ability, （）.
A.the manager was assigned a challenging task B.the manager assign a challenging task C.the board assigned him a challenging task D.a challenging task was assigned to the manager
单项选择题 There are approximately 500 （） now in operation in the United States.
单项选择题 Our factory is much more productive now. This year’s production is five times as much （） it was ten years ago.
单项选择题 When you write, （） all the necessary information.
