题目内容

在不同的pH值范围内，指示剂颜色会随pH值而变化，因此必须控制合适的pH值范围。

A. 对
B. 错

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以下程序的执行结果是________。 #include＜iostream.h＞ class base public： virtual void who() cout＜＜"base class"＜＜end1； ; class derrvel: public base public: void who() cout＜＜"derivel class"＜＜end1；； class derive2：public base public: void who()cout＜＜"derive2class"＜＜end1；； void main() base obj1，*P； derivel obj2； derive2 obj3； p=&obj1： p-＞who()； p=&obj2； p-＞who()； p=&obj3； p--＞who()：

滴定突跃是指滴定曲线上垂直上升的那段曲线所对应的pH值范围。

A. 对
B. 错

以下程序的执行结果是【10】。#include＜iostream.h＞class Sampleint n;public:Sample() Sample(int m) n=m; int &operator--(int)n--;return n;void disp() cout＜＜"n="＜＜n＜＜end1; ;void main()Sample s(10);(s--)++;s. disp();

Almost everyone in the world uses oil in some way. Without oil, the world will stop, so men look for it everywhere. Oilmen drill for oil in deserts, in mountains and under the sea. Quite often they find nothing, but the search for oil always goes on. Oil is very important because none of our machines can run without it. Big ships carry oil everywhere. Perhaps the oil in your motorbike or in your father’s car comes from somewhere far away. Perhaps it comes from Iraq or Venezuela. Cars and motorbikes need oil, and so do many other things. How many things can you name Oil is very important for us.

A. [A] True.
B. False.