It worried her a bit_______her hair was turning grey.
The sick salesman was happy to stay at home because doing _____ was a thorough rest for him.
Sorry, sir, but you can’t go any further without______boarding pass. Please obey ____ rule.
Eyes ________, I see the moon so bright; Head ________, in homesickness I am drowned.
The shoes are of high quality and ________ long.
--The research on the new bird flu virus vaccine is challenging and demanding. Who do you think can do the job?--________ my students have a try?