________of the chemical factories in their city _________pouring waste water into the river. It’s too dangerous.
| A．Two fifths; are | B．Two fifths; is | C．Two fifth; are | D．Two fifth; is |
He _______ this book for four years. He _______ it in 2011.
| A．has bought; bought | B．bought; bought |
| C．has kept; has bought | D．has had; bought |
Sorry, I _______ to help you at nine. I was busy at that time.
| A．won’t come | B．can’t come | C．didn’t come | D．shouldn’t come |
His sister _______ from home for a long time.
| A．has left | B．has been away | C．left | D．will leave |
To improve his riding skills, he spends _______ an hour a day practicing riding.
| A．at last | B．at least | C．at once | D．at all |
Jim said he _______ dinner. He was quite full.
| A．had had | B．was having | C．had | D．had eaten |