With the word “PM2.5” ____ appearing in media reports, people pay greater attention to it and seek health tips for smoggy days.
| A．constantly | B．instantly | C．roughly | D．firmly |
Having checked the doors were closed, and _________ all the lights were off, the boy opened the door to his bedroom.
| A．why | B．that | C．when | D．where |
Do not let any failures discourage you, for you can never tell ______close you may be to success.
| A．how | B．that | C．which | D．where |
It is suggested that all these gifts be mailed immediately _________ in time for Christmas.
| A．in order to have received | B．so as to receive |
| C．so as to be received | D．so as to be receiving |
Chinese scientists have produced an embryo of a giant panda through cloning technology,_____ is a breakthrough ______ could save the endangered animals.
| A．that; which | B．which; that | C．which; what | D．that; what |
“Hope for the best and prepare for the worst” is a proverb,_______life is beautiful and full of frustrations as well.
| A．to mean | B．meaning | C．means | D．meant |