4. Answer A, B, C or D: If x is measured in meters, r(x) is a function of x and r is also measured in meters, and ρ is measured in kg.m, then what is the unit of
(A) kg.m^-1
(B) kg.m
(C) kg
(D) kg.m²

48.__________.First of all, turn off as many "push” notifications as possible. You don't have to be interrupted by every "like" that your latest Instagram picture receives. Next, take distracting apps off your home screen. Keep the apps that you want to encourage yourself to use front and center, but move anything to folders on your second page of apps. Which of the followings is the most appropriate topic sentence (to be put at the beginning of the paragraph to introduce the main idea of the paragraph)?(A) The following steps will help you stop checking your phone so much.(B) "Push" notification is the most annoying smartphone feature.(C) Turning off "push" notification is easier than taking apps off home screen.(D) "Push" notification is the main cause of distraction from smartphones.

49. People have been cutting back their meat consumption slowly but surely. According to a 2018 Dalhousie University poll study, this downward trend of consuming less meat is likely tocontinue - at an even faster pace.________The meat-free trend has become even more dramatic.Which of the followings is the most appropriate supporting sentence (to be put in the blank)?(A) This is likely to lead to a serious consequence of food shortage, especially meat, in developing countries.(B) Dietitians from Toronto General Hospital worried that this trend will have a negative effect on nutrient intakes.(C) This study suggested that university students need more incentives to reduce their meat consumption.(D) One-third of respondents indicated a willingness to reduce their meat consumption in the near future.

50. When you are in a safari vacation, the rule of thumb is to pack light. Your luggage may be limited to a small duffel bag, so try to limit your clothes to whatever is necessary. For example, bring enough clothes for two days only.______Then, you can dry the clothes in the sun.Which of the followings is the most appropriate supporting sentence (to be put in the blank)?(A) Safari camps generally provide laundry service for you to wash the clothes by hand.(B) You should avoid wearing white clothes because it attracts animals' attention easily.(C) Black and other dark colors are recommended because they are less obvious when they get dirty.(D) The best way is to dress in layers as the areas can be chilly in the mornings and late afternoons.

3. Answer A, B or C: If y = f(u) and u = g(x), where f and g are twice differentiable such that g'(x) = g(x), then equals...(A)(B)(C)

5.Answer A, B, C or D: Which of the following expressions is WRONG? If you think they are all correct, answer D.(A)= f(g(b)) - f(g(a))(B)= f(g(b)) - f(g(a))(C)= f(g(b)) - f(g(a))(D) None of the above.

1. Mark Zuckerberg, Facebook's chief, is testing a software that will put children in _______ of their own learning, recasting their teachers as facilitators and mentors.(A) responsible(B) place(C) charge(D) lead

2. In just a few years, technology giants have begun remaking the very nature of schooling on a vast scale, _______secondary schools nationwide.(A) impacting(B) ranging(C) limiting(D) impressing

3. Some tech teachers believe that applying an engineering mindset can improve about any system, and that these tech giants' business insights _______ them to rethink the country's education.(A) embrace(B) enable(C) enrich(D) enhance

4. Given the changes in innovations with artificial intelligence and automation, some tech leaders are experimenting different models to find out which can _______ better results.(A) establish(B) apply(C) cause(D) yield

5. About a decade ago, when Amazon introduced its first e-reader, publishers_______ that digital books would take over the industry, the way digital transformed the music industry. And for a while, that fear seemed totally justified.(A) captured(B) concerned(C) panicked(D) prohibited