The analysis shows that plastics, particularly those that __________ fast, are contributing to the climate change.
| A．break off | B．break down |
| C．break up | D．break out |
He ＿＿＿articles for our wall-newspaper these three years, and he ＿＿＿about forty articles.
| A．has been writing； has written | B．has been writing； wrote |
| C．is writing； has been writing | D．has written； has written |
The children ＿＿＿＿＿＿ very quiet； I wonder what they ＿＿＿＿up to.
| A．were； are being | B．are being； are | C．are； do | D．are being； do |
Jim talked for about half an hour yesterday.Never＿＿＿＿＿ him talk so much.
| A．I heard | B．did I hear | C．I had heard | D．had I heard |
—— ＿＿＿＿＿ Betty this morning?
—— Not yet, but she is sure to be here before noon.
| A．Have you seen | B．Will you see | C．Do you see | D．Did you see |
—— Are you a visitor here?
—— That’s right.I＿＿＿round the world and now my dream of coming to China＿＿＿true.
| A．have traveled； has come | B．was traveling； had been come |
| C．am traveling； has come | D．have traveled； has been come |