单选题If he had been in better health, he ______ more books. A．can write B．could have written C．could write D．have written

单选题Mr. Smith used to smoke______but he has given it up recently.

单选题I can' t tell the ______ difference between the twin sisters.

单选题David tends to feel useless and unwanted in a society that gives so much ______ to those who compete well.

单选题Under ethical guideline recently adopted by the National Institutes of Health, human genes are to be manipulated only to correct disease for which ______ treatments are unsatisfactory.

单选题We do not mean to be disrespectful when we refuse to follow the advice of our leader.

单选题Compared mathematically to smoking and driving, almost everything else seems relatively risk-free, ______ almost nothing seems worth regulation.

单选题The sheer diversity of tropical plants represents a seemingly ______ source of raw materials, of which only a few have been utilized.

单选题He has just taken an examination ______chemistry.

单选题 What enables some people to get big creative breakthroughs while others only get small and non-creative breakdowns, blaming themselves and society? Are some people gifted? Are there other factors 21

单选题The Labour defeat was a disaster, but it might be a blessing ______.

单选题—Why didn't you go to the cinema yesterday? —I______, but my daughter returned from America the moment I was leaving.

单选题GIF files are limited to a maximum of 8 bits/pixel, it simply means that no more than 256 colors are allowed in ______. A．an image B．a file C．a window D．a page

单选题A: Why were only three of you present at the meeting? B: ______.

单选题(Thirteen hundred) medical professionals, (all of which) have been trained to treat drug dependency, (attended) the annual convention (sponsored) by a society.

单选题The research scientists often meet with problems______new types of instruments for their solution.

单选题As many office workers adapt to remote work, cities may undergo fundamental change if offices remain under-utilized. Who will benefit if working from home becomes the norm? Employers argue they make considerable savings on real estate when workers shift from office to home work. However, these savings result from passing costs on to workers. Unless employees are fully compensated, this could become a variant of parasitic (寄生的) capitalism, whereby corporate profits increasingly rely on extracting value from the public—and now personal—realm, rather than on generating new value. Though employers are backed by a chorus of remote work advocates, others note the loneliness, reduced productivity and inefficiencies of extended remote work. If working from home becomes permanent, employees will have to dedicate part of their private space to work. This requires purchasing desks, chairs and office equipment. It also means having private space dedicated to work: the space must be heated, cleaned, maintained and paid for. That depends on many things, but for purposes of illustration, I have run some estimates for Montreal. The exercise is simple but important, since it brings these costs out of the realm of speculation into the realm of meaningful discussion. Rough calculations show that the savings made by employers when their staff works from home are of similar value to the compensation workers should receive for setting up offices at home. What does this mean for offices in cities? One of two things may happen: Employers pass these costs onto employees. This would be a form of expropriation (侵占), with employees absorbing production costs that have traditionally been paid by the employer. This represents a considerable transfer of value from employees to employers. When employees are properly compensated, employers’ real estate savings will be modest. If savings are modest, then the many advantages of working in offices—such as lively atmosphere, rapidity of communication, team-building and acclimatization (适应环境) of new employees—will encourage employers to shelve the idea of remote work and, like Yahoo in 2013, encourage employees to work most of the time from corporate office space.

单选题We are using up our natural resources too quickly and at the same time we are ______ our environment with dangerous chemicals.

单选题On hearing the bad news, he got up quickly, ______ the lunch unfinished.

单选题A: I'm sorry I'm calling you so late.B: ______okay.