关于会议文献，正确的说法有（） A.会议文献是学术会议的成果 B.出版类型较少，但收

下列叙述中错误的是______。
(A) 在数据库系统中，数据的物理结构必须与逻辑结构一致
(B) 数据库技术的根本目标是要解决数据的共享问题
(C) 数据库设计是指在已有数据库管理系统的基础上建立数据库
(D) 数据库系统需要操作系统的支持

Олег кажется куда-то собирается.Мужчина в сером костюме кажется мне знакомым.

Car crashes are the leading cause of injury and death among U.S. children, and though most of us now think of car seats as standard baby equipment, about half of all children under the age of four who died in vehicle accidents last year were not restrained. It is calculated that only about two-thirds of children ages five to fifteen buckle their seat belts.
Moreover, the traffic-safety agency estimates that even among parents who always strap their children in, 85% are not doing it properly. They often don’t know where best to place the kids, don’t use the proper restraint for their age and weight, or don’t install the safety seats properly. Despite the reports about front seats collapsing onto back seats when certain car models get in accidents, the safest place in the car for any child up to the age of 12 is still the back seat. Babies up to 9 kg and one year old should ride in rear-facing infant seats.
Never place a child under age 12 in the front seat with a working passenger-side air bag. These devices are discharged at 320 km/h and can be triggered by low-speed fender benders. They have killed 77 kids in the U.S. since 1993. If you must place a child in front, make sure the passenger-side bag is switched off.
Children over age one should ride in forward-facing safety seats with a five-point harness system. A child who weighs at least 18 kg or at least 1m high can graduate to a booster seat that elevates her so that the standard shoulder and lap belt fits properly.

Which of the following is NOT among the "improper ways" mentioned in the passage

A．They don’t know where best to place the child.

B．They don’t have the safety equipment for the child.

C．They don’t use the proper restraint for the kid’s age and weight.

D．They don’t install the safety seats properly.

提供合成尿素分子中第二分子NH₃的物质是______。

A．亮氨酸
B．天冬氨酸
C．色氨酸
D．脯氨酸
E．精氨酸