下列云类中属于低云的是（）。A.Actra B.Cc C.Ns D.Cidens

Alan is a 16-year-old boy. He is the only child in his family. Alan is an American high school student. He lives in New York. Art and music are his favourite subjects(科目). He loves studying and also love sports. He usually goes swimming three or four times every week. Alan’s father works in a restaurant(饭店) near New York. He likes swimming, too. So Alan often go swimming with his uncle. Cool water always make him happy. American students are different(不同的) from us. On Saturdays, he often has parties (派对) with his friends and they always enjoy themselves. On Sundays, he usually studies at home and watches sports programs(节目). His favourite drink is Coke, but Coke is an unhealthy drink. He often eats vegetables and he often does some sports to keep healthy. (健康)

小题1:Alan’s father is a _________. .

A．teacher

B．waiter(服务员)

C．reporter（记者）

D．student小题2:Alan likes ____________________.

A．Art and music

B．singing and sports

C．studying and sports

D．A and C小题3:How many people are there in Alan’s family ?

A．1

B．3

C．4

D．5小题4:What does Alan often do on Sundays ?

A．He often go swimming with his father.

B．He often has parties with his friends.

C．He usually studies at home and watch TV.

D．He always does some sports.小题5:What’s the meaning of the underline (划线) word, “unhealthy” in the passage ?

A．不健康的

B．美味的

C．有营养的

D．受欢迎的

下列关于共同共有特征的表述中，错误的是（）

A．共同共有也具有确定的份额

B．共同共有关系存在期间，共有人不能划分自己对财产的份额

C．共同共有关系消灭时，可以对共有财产进行分割

D．共同共有的共有人平等地享有权利和承担义务

什么叫表压？

用手握住瓶子，使瓶子在竖直方向静止，如果握瓶子的力加倍，则手对瓶子的摩擦力（　　）

A．大小不变

B．大小加倍

C．方向向上

D．方向由向上变为向下

问题解决的特征有目的性、______和序列性。