When I entered the classroom, I saw Mary ______ at the desk and ______ a letter.
| A．seating; writing | B．seated; wrote | C．sitting; wrote | D．seated; writing |
_____ a reply, I decided to write another letter.
| A．Not receiving | B．Not received |
| C．Not having received | D．Having not received |
We were having a picnic when _______ there came a downpour, which was really a wet blanket.
| A．all at once | B．in addition |
| C．in return | D．as well |
______ the books, he realized they were far from enough and told some of us to share.
| A．Having counted | B．Counts |
| C．To have counted | D．Counted |
Gary was behaving as if nothing _______.
| A．happened | B．has happened |
| C．had happened | D．will happen |
Father _____ our washing machine the whole morning. He must get it done before lunch.
| A．has repaired | B．repairs |
| C．will repair | D．has been repairing |