Scientists are convinced _ the positive effect of laughter physical
and mental health.
| A．of; at |
| B．by; in |
| C．of; on |
| D．on; at |
The topic, we devoted a full discussion, is to be presented to our teacher at class.
| A．which | B．where | C．to which | D．for which |
Unless you have planted something, you won’t be able to know the pleasure of watching the thing you have planted .
| A．grown | B．growing | C．to grow | D．to be grown |
These interesting articles were written by Anna, who for our magazine these years.
| A．wrote | B．would write |
| C．is writing | D．has been writing |
for his expert advice, John is often asked to help others with their personal affairs.
| A．Having known | B．Being known |
| C．Known | D．Knowing |
I suggest you save you find with an electronic bookmark so you can return to it later.
| A．what | B．that | C．how | D．where |