He didn’t make _____ clear why he was late again.
| A．it | B．that | C．this | D．those |
---I’ll thank you my affairs alone.
---I will. It’s none of my business.
| A．leaving | B．to leave | C．for leaving | D．not to leave |
He 20 dollars for his old bike the other day.
| A．paid | B．took | C．spent | D．offered |
It is much easier to talk about social change than to .
| A．bring it on | B．bring it about | C．bring it up | D．bring it out |
This is a story completely by him, so don’t rust him.
| A．discovered | B．invented | C．found | D．known |
Historical experience can as a most important source of information.
| A．serve | B．use | C．regard | D．prove |