—Such a mistake could have been avoided.
—Unfortunately, he _______ the mistake again and again.
| A．repeated | B．would repeat |
| C．had repeated | D．would have repeated |
I consider____ my duty to help you．
| A．it | B．this | C．that | D．its |
Is＿possible to fly to the moon in a spaceship?
| A．now | B．man | C．that | D．it |
Is＿necessary to tell his father everything?
| A．it | B．that | C．what | D．he |
There is a photo on the wall.____ the photo of Lei Feng.
| A．It | B．Its | C．It's | D．He |
Children can usually dress ______ by the age of five.
| A．him | B．them | C．himself | D．themselves |