搜题请搜索小程序“爱下问搜题”
问题 选择题

下列说法中正确的是（　　）

A．一物体向东直线运动，突然施加一向西的力，物体可能立即向西运动

B．物体的加速度一定和物体所受合外力同时产生，同时消失，且方向永远一致

C．在月球上举重比在地球上容易，所以同一个物体在月球上比在地球上惯性小

D．运动物体受到的摩擦力的方向一定和它的运动方向相反

答案

A．一物体向东直线运动，突然施加一向西的力，物体应向东做匀减速运动，但速度方向不会立即向西，故A错；

B．力是产生加速度的原因，物体的加速度一定和物体所受合外力同时产生，同时消失，且方向永远一致，故B正确；

C．惯性只跟质量有关，跟其他任何因数无关，故C错误；

D．运动物体受到的摩擦力的方向一定和它的相对运动或相对运动趋势方向相反，故D错误．

故选B．

单项选择题

氟骨症摄影体位，正确的是 （）

A.双手正位

B.腕关节正位

C.骨盆正位

D.颅骨正侧位

E.双腕关节正侧位
查看答案
单项选择题

Questions 16～20


Napoleon famously described the British as a nation of shopkeepers. These clays it would be equally true to describe them as a nation of shoppers. Either way, London is the UK’s shopping mecca; if you can’t find it here you probably can’t find it at all.
Some London shops are more or less tourist attractions in their own right. Few visitors come away without popping into Harrods. This famous store is a real one-off. The toilets are lab, the food hall enough to make you swoon, and if they haven’t got what you want, it probably doesn’t exist. No other store has such a sense of sheer, outrageous abundance. Since Absolutely Fabulous brought Edina and Patsy steaming onto our screens, Harvey Nichols ("Harvey Nicks") has become another must-see attraction. It boasts a great food hall, an extravagant perfume department and jewellery to save up for. But with all the big names from Miyake to Lauren, Hammett to Calvin Klein and a whole floor of up-to-the-minute menswear, it’s fashion that Harvey Nichols does better than the rest. The selection is unrivalled and the prices high, although the sales offer some great bargains, and the store’s own clothing line is reasonable.
Carnahy Street still reeks of the 60s although it’s had something of a revival since the "Cool Britannia" kick brought Union Jack dresses back into fashion. The last punks have long since slunk away from Chelsea’s King’s Rd but there are still plenty of interesting shops slotted in amid the high-street chains.
Oxford St and classier Regent St come into their own in the six weeks running up to Christmas when they’re festooned with lights. At other times of the year Oxford St can be a great disappointment. Selfridge’s is up there with Harrods as a place to visit and the farther east you go the tackier and less interesting it becomes.
Although most things can be bought in most parts of town, there are also streets with their own specialties; Tottenham Court Rd, for example, is one long electrical goods shop (watch out for rip-offs though), while Charing Cross Rd is still the place to come for offbeat books.
Many tourist attractions have excellent shops selling good-quality souvenirs like mugs, pens, pencils, stationery and T-shirts, often with themes to match their content (war books and videos at the Imperial War Museum). By buying from these shops you help contribute towards the building’s maintenance, especially important in the cases of those without entry charges.

The word "revival" (para. 3) means ______.

A. cooling off
B. holding sway
C. coming back
D. firing up
查看答案