23. With the economic situation worsening _______, shopkeepers have to sell their goods ______ a big discount to attract customers.
| A．day by day; with | B．day after day; at | C．day by day; at | D．day after day; in |
___ the temperature might drop, coal was prepared for warming.
| A．To consider | B．Considered | C．Considering | D．To be considered |
We had a really bad time about six months ago but now things are ____.
| A．looking up | B．coming up | C．making up | D．turning up |
--- 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?
| A．Shall | B．Must | C．Will | D．May |
He is only too ready to help others, seldom, ____, refusing them when they turn to him.
| A．if never | B．if ever | C．if not | D．if any |
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）.
| A．with whom | B．to whom | C．through which | D．for which |