唇系带矫正术的描述正确的是（） A.横向切断系带后将创面横向缝合 B.横向切断系带后

如果|a+1|+（b-2）²=0，求（a+b）²⁰¹¹+a²⁰¹⁰的值．

论述哪些不是传统发展模式的特征（  ）

A．高投入

B．高消耗

C．无污染

D．高污染

在恒温、恒容的密闭容器中发生反应A（g）B（g）＋C（g），若反应物的浓度由2 mol/L降到0.8 mol/L需20 s，那么反应物浓度由0.8 mol/L降到0.2 mol/L所需的时间为

A．10 s

B．大于10 s

C．小于10 s

D．无法判断

水平传播

You probably won’t be shocked to find out that the inventor of tire rubber is Charles Goodyear, as he’s the only guy on the list to actually get his name attached to the end product. (46) It wasn’t easy coming up with a form of rubber tough enough to withstand the drag racing and car chases everyone envisioned the day the automobile was invented. In fact, if there was one man who should have given up his life dream, it was Goodyear. (47)The man spent time in and out of prison, lost every friend he had and starved his children in his tireless pursuit of a per form of rubber.

(48) After his first two years of tinkering and failing with primitive rubber in the 1830s, Goodyear and his family were camping out in an abandoned factory and fishing for sustenance. This is when he made a huge breakthrough: He’d use acid to smooth out and toughen rubber! The government bought 150 mailbags made of the stuff and the rest is...

Oh, wait. They were all defective. The process didn’t work and Goodyear was ruined. Again.

Finally in 1839, Goodyear wandered into a general store with another failure of a formula. The crowd watched and laughed at him. (49)In a rage, he began to shake his fist, flinging a piece of his rubber onto the hot stove top.

After inspecting the charred remains, he realized that he had just found a way to make durable, weatherproof rubber. (50) Despite what we’re sure were numerous failed "now let’s try setting this on fire to see if it improves it!" experiments, an empire was born.

(46) It wasn’t easy coming up with a form of rubber tough enough to withstand the drag racing and car chases everyone envisioned the day the automobile was invented.