Scientists are convinced_____the positive effect of laughter_____physical and mental health.
| A．of; at | B．by; in | C．of; on | D．on;at |
. Little ______about his own health though he was very ill.
| A．he cared | B．he cares | C．does he care | D．did he care |
The light will be thrown ______ the cause of cancer by research that is now in progress.
| A．to | B．upon | C．in | D．for |
—Why was he unhappy yesterday?
—A letter from home ______ an attack of homesickness.
| A．set off | B．set out | C．set about | D．set up |
______great progress Jim had made in _______ time!
| A．What a ; such a short | B．What ; so short a |
| C．How a ; such a short | D．How; such short |
When I wanted to buy a computer, I saved as much as I could, and my motherthe rest of the money.
| A．kept up | B．held up | C．tool up | D．made up |