_____ all the inventions have in common is ______ they have succeeded.
| A． What; what | B． That; what |
| C． What; that | D． That; that |
Scientists are convinced ______ the positive effect of laughter ______ physical and mental health.
| A．of；at | B．by；in | C．of；on | D．on；at |
In American there are more households with pets than ______ with children.
| A．those | B．these | C．ones | D．that |
They are said to have developed a new ______ to teaching, which is said to improve classroom teaching greatly.
| A．method | B．means | C．way | D．approach |
The first one ______ will get a beautiful gift.
| A．arrived | B．arriving | C．arrives | D．to arrive |
Children, who grow up in a friendly family, are more ______ to get along wellwith others.
| A．similar | B．probable | C．likely | D．possible |