完形填空
A robot is a special kind of machine. It is a machine that can follow instructions( 命令).
1 it is a machine, it hardly makes mistakes or gets tired. And it 2 complains, unless you tell it to!
Robots are around us. Some robots are used to 3 things. For example, robots can help make cars. Some robots are used to explore(勘察) dangerous places. Some robots can help clean your house. Some robots can even 4 human languages. They can be used to help answer telephone calls. Some robots look like 5 , but most robots do not. They just look like machines.
Long ago, people imagined 6 . Over 2,000 years ago, Homer, a famous poet, imagined robots. His robots were made of gold, but they were not 7 . Nobody was able to make a real robot at that time. The 8 real robot was made in 1961. It was called Unimate.
In the future, we will have even more robots. They will do things that we can't do, or that we don't want to do, or that are too 9 for us. For example, robots will help us fight fires and illnesses and 10 things. They will help make our life better.
xC(g)+D(s)，t1时达到平衡。在t2、t3时刻分别改变反应的一个条件，测得容器中气体C的浓度随时间变化如图所示。下列说法正确的是