At school, some students are active, ______ some are shy, yet they can be good friends with one another.
On September 8th, Obama, President of America, made an inspiring speech at the school opening, which has left a lasting ___________ on the audience.
John’s quick action shows that ________ knowledge of first aid can makereal difference in saving a person’s life.
-----“________, sir?” -----“No. Go ahead.”
In the environment area, there is a system ________ the waste is disposed of by using the principles of ecology.
After the recovery from her illness, my mother began to writing something as a way to kill her time.