题目

在生活与生产中，常见的直线运动是变速直线运动。物理问题中，当涉及的各矢量的方向在同一条直线时，可在这些量的量值（大小）前冠以正（+）、负（-）号表示这些矢量，量值表示其大小，正、负号则表示其方向。下列各组给出的是匀变速直线运动质点0时刻的速度及运动过程的加速度，则从0时刻开始做加速直线运动的是（） A . v0=10 m/s，a=-2 m/s2 B . v0=-10 m/s，a=-2 m/s2 C . v0=-10 m/s，a=2 m/s2 D . v0=10 m/s，a=2 m/s2 Sitting in a dark movie theater with your friends. and a tub of popcorn (H^) sounds like a perfect way to spend a Saturday night, and it could be, if you are willing to share your popcorn with the entire row of moviegoers around you. A review of movie-theater popcorn reveals an alarming amount of fat, salt and calories in even the smallest sizes. A large tub of popcorn at Regal Cinemas, for example, holds 20 cups of popcorn and has 1,200 calories, 980 milligrams of sodium (钠) and 60 grams of saturated (饱和的) fat. Adding just a tablespoon of butter adds 130 calories. And do not forget that it comes with free refills. Not so hungry? The medium size popcorn, even the small, at 11 cups, delivers 670 calories, 550 milligrams of sodium .and 24 grams of saturated fat. The findings may surprise those who believe it is a relatively healthy snack. In fact, plain air-popped popcorn is low in calories and free of saturated fat. Movie theater popcorn, however, is popped in oil, often coconut oil, which is 90 percent saturated fat. Add salt to it, and your once-healthy snack turns into a health offender. One way to make your popcorn healthier? Ask the theater to pop the corn without salt. The best way to make your movie snack healthier, however, would be to skip the popcorn. "You could share a tub of popcorn with 10 friends," Dr. Nestle, a professor of nutrition at New York University, said. "Or, what a concept, watch the movie without eating anything." 1.The review finds that movie theatre popcorn may contain all the following EXCEPT ______. A. butter           B. sodium           C. saturated fat         D. pepper 2.What does the author think of popcorn prepared in coconut oil? A. It is a healthy snack.                       B. It does harm to our health.               C. It looks like a perfect choice.                D. It is very nutritious. 3.Which kind of popcorn causes the least health concern? A. Movie theatre popcorn.                   B. Popcorn sold at Regal Cinemas.          C. Large size popcorn.                        D. Plain air-popped popcorn. 4.What is Dr. Nestle's suggestion to moviegoers? A. Avoid eating popcorn.                    B. Share popcorn with friends.              C. Not eating anything in the movie theatre.      D. Try eating other kind of food.