—Ready to give up guessing, Sandy? —No, no. Hold on! I think I _______ at the answer now.
___ the temperature might drop, coal was prepared for warming.
We had a really bad time about six months ago but now things are ____.
--- 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?
He is only too ready to help others, seldom, ____, refusing them when they turn to him.
Encouraged by my science teacher, I set about my studies on developing my product, _____I hope I will succeed in applying for a patent(专利).