24—Hi, Alice, you look tired—I am tiredI__________ the living room all day

Because of the ________ of her pet dog, Jenny was so sad and cried for a long time.

(2013·长沙二模)—The research on the new flu virus vaccine is challenging and demanding.Who do you think can do the job?—________ my students have a try?

youknown each other for long－Not verylong, ____________ we started to work in the company.

Two places of interest in Beijing are well-known to people from home and abroad. One is the Great Wall. ___________ is the Summer Palace.