下列函数中是指数函数的个数为（ ）①y=（12）x ②y=-2x ③y=3-x

Flags have existed for over 3,000 years. The earliest flags were wooden or metal poles with a carving. About 2,000 years ago pieces of fabric were added to some poles for decoration. Over the next 500 years the free-flying part of the flag became more important.

小题1:The earliest flags have a long history for more than _______ years.

A．2000

B．500

C．3000

D．2500小题2:The flying pieces of flags were added to some poles for _______ about 2000 years before.

A．passion

B．decoration

C．progress

D．sincerity小题3:The flag which features a temple belongs to ___________.

A．Japan

B．Nepal

C．Singapore

D．Cambobia小题4:An olive wreath is used to represent ________________.

A．peace

B．purity

C．justice

D．Equality小题5:Two flags that include the sun in their design belong to __________________.

A．Nepal and Japan

B．Singapore and Japan

C．the United Nations and Nepal

D．the United Nations and Singapore

图中a、b、c为三个物块，M、N为两个轻质弹簧，R为跨过光滑定滑轮的轻绳，它们连接如图并处于平衡状态

①有可能N处于拉伸状态而M处于压缩状态

②有可能N处于压缩状态而M处于拉伸状态

③有可能N处于不伸不缩状态而M处于拉伸状态

④有可能N处于拉伸状态而M处于不伸不缩状态

以上叙述正确的是（　　）

A．①③

B．①④

C．②③

D．①②③④

可简化成1个约束和2个自由度的支座为（）。

A.可动铰支座

B.固定端支座

C.固定铰支座

D.自由端

当今陆地上最高、最雄伟的山系是（）和（）。

心肺复苏的开放气道、救生呼吸和人工循环都是从判定开始，只有经过正确判定，才能确定对患者进行心肺复苏。因此，判定是一个对患者进行观察和了解的过程。（）