甲、乙、丙三个同学排成一排拍照，则甲排在中间的概率是（ ） A．16 B．14 C．1

经线指示东西方向，纬线指示南北方向．______．（判断对错）

只能用于软钎焊、钎焊小件的是（）。

A.烙铁钎焊

B.火焰钎焊

C.气相钎焊

D.感应钎焊

All known techniques for handling complex problems successfully seem to fall into one of the three classes: subdividing the problem (51) , ignoring irrelevant detail in a safe way (52) , and having an independent agent (53) the internal consistency (contextual checking). The first two provide guidelines for solving the problem, the third serves to provide early warnings. A good programming language supports all three.
In subdividing problem, some of the subproblems may be similar to the (54) problem. It leads us to a (55) solution. This (55) solution is viable provided each of the subproblems is easier to solve than the original problem.

A．abrogation

B．abstraction

C．composition

D．contraction

由形态相似、功能相关、起源相同的细胞和细胞间质组成了动物的（）。

A、器官

B、系统

C、有机体

D、组织