—Please go on with your demonstration．
—But where was I?
—Well, you_____the two chemicals together．
| A．tried to mix | B．were trying to mix |
| C．were trying mixed | D．had tried to mix |
Not until he left his home _____ to know how important the family was for him.
| A．did he begin | B．had he begun |
| C．that he began | D．he had begun |
With more forests _____being destroyed, huge _____ of good earth _____ washed away each year.
| A．are ; number ; is | B．/ ; quantities / are |
| C．be ; number ; are | D．/ ; quantities ;is |
I just wonder _____ that makes him so excited?
| A．why it does | B．what he does |
| C．how it is | D．what it is |
---I don’t think your children could have been used to the quick pace of life while working in Shenzhen, _____they?
---_____. They thought of returning to Changchun.
| A．had ; Yes | B．do ; Yes | C．have ; No. | D．were ; No |
Parents are taught to be aware of _____ important mental health is to their children.
| A．that | B．how | C．what | D．so |