钝角三角形三边长为a,a+1,a+2,最大内角不超过120°，则a范围是_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题填空题

钝角三角形三边长为a,a+1,a+2,最大内角不超过120°，则a范围是

答案

长度a+2所对角最大，设为

，得

单项选择题

接过别人递来的名片，首先应该（）。

A.放入衣袋

B.拿在手上把玩

C.认真快速默读一遍

D.交予他人

单项选择题

C

Americans use more water than any other people in the world. If we continue to use water at the rate we do now, we will soon not have enough to meet our needs. In 1980, 40 billion gallons were used each day in the United States. In 1990, 700 billion gallons were used. The average Americans use almost 90 gallons of water a day for personal use. And much move water is needed to make the things American people like to have. For example, it takes thousands of gallons of water to make one pound of beef for the dinner table. It takes more than 100000 gallons of water to make a car. If we include these uses of water, the average American uses about 2000 gallons of water a day．

Which is NOT TRUE according to the passage7 ( )

A．Americans may run short of water in the future.

B．Americans use more water than ever.

C．Americans use as much water as they used to.

D．The more things Americans like to have, the more water is neede