一快艇要从岸边某处到达河中离岸100m远的浮标处,已知快艇在静水中的速度图象如图

题型:选择题

问题:

一快艇要从岸边某处到达河中离岸100m远的浮标处,已知快艇在静水中的速度图象如图甲所示,流水的速度图象如图乙所示,假设行驶中快艇在静水中航行的分速度方向选定后不再改变,则

A.快艇的运动轨迹可能是直线

B.快艇的运动轨迹一定是曲线

C.最快到达浮标处通过的位移为100m

D.最快到达浮标处所用的时间为20

考点:运动的合成与分解
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多数投保人很难全面了解保险商品的保险责任、保险金额与保险费率之间的关系,这就需要保险经纪人充分考虑投保人的实际保险需要,帮助投保人以最少的保费开支获得最大的( )。

A.投资收益

B.保险责任

C.保险救济

D.保险保障

题型:选择题

The old-fashioned general store is fast disappearing. This is, perhaps, a pity, because shopping today seems to lack that personal contact which existed when the shopkeeper knew all his regular customers personally. He could, for instance, remember which brand of tea Mrs. Smith usually bought or what sort of washing-powder Mrs. Jones preferred. Not only was the shop a center of buying and selling, but also a social meeting place.

A prosperous general store might have employed four or five assistants, and so there were very few problems in management as far as the staff were concerned. But now that the supermarket has replaced the general store, the job of the manager has changed completely. The modern supermarket manager has to cope with a staff of as many as a hundred, apart from all the other everyday problems of running a large business.

Every morning the manager must, like the commander of an army division, carry out an inspection of his store to make sure that everything is ready for the business of the day. He must see that everything is running smoothly. He will have to give advice and make decisions as problems arise, and he must know how to get his huge staff to work efficiently with their respective responsibilities. No matter what he has to do throughout the day, however, the supermarket manager must be ready for any emergency that may arise. They say in the trade that you are not really an experienced supermarket manager until you have dealt with a flood, a fire, a birth and a death in your store.  (Note: Answer the questions or complete the statements in NO MORE THAN TEN WORDS.)

小题1: Why is it a pity that there are fewer old-fashioned general stores now? _____________________________.

小题2: The shopkeeper was often the most well-informed person in the neighborhood because _____________________________.

小题3: The words “… a flood, a fire, a birth and a death …” in the last sentence refer to _____________________________.

小题4: What must the manager do every morning? ___________________________.

题型:选择题

cI基因的表达抑制λ噬菌体进入溶源状态。

题型:选择题

关于过期妊娠,正确的是

A.停经超过42周者为过期妊娠

B.过期时间越长,围产儿死亡率越高

C.胎儿在宫内情况与胎盘功能无关

D.过期时间越长,胎儿发育越好

E.过熟儿说明胎盘功能良好

题型:选择题

根据产生正弦波振荡的相位平衡条件可知,振荡电路必须为()反馈。

A.负;

B.正;

C.无;

D.电压并联负。

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