在没有与民工签定有效协议或没有路工带领时民工是否可以上道作业？

阅读理解。

     Malls are popular places for Americans to go. Some people spend so much time at malls that they are

 called "mallrats (老鼠)". Mall rats shop until they drop in the hundreds of stores.

    People like malls for many reasons. They feel safe because malls have police stations, parking is usually

 free, the weather inside is always fine. The newest malls have beautiful rest places with waterfalls (瀑布)

 and large green trees.

      The largest mall in the United States is the Mall of America in Minnesota. It covers 4. 2 million square

 feet (英尺). It has 350 stores, eight nightclubs, and a large park! There are parking spaces for 12,750

  cars. About 750,000 people shop there every week.

      The first indoor mall in the United States was built in1965 in Edina, Minnesota. People love doing all

 their shopping in one place. More malls are built around the country .Now malls are like town centers

 where people come to do many things. They shop, of course, they also eat in food courts (广场) that

 have food from all over the world. They see films at the theaters. Some people even get their exercise

 by doing the new sport of "mall walking". Others go to malls to meet friends.

     In some malls, people can see a doctor and even go to the church. In other words people can do just

 about everything in malls. Now people can live in their favorite shopping center in fact.

1. Here "mall" means ____.

    A. a large park

    B. a big church

    C. a square

    D. a shopping center

2. Why do people like malls

    A. Because they can plant green trees there.

    B. Because they enjoy the waterfalls there.

    C. Because they feel safe and comfortable there.

    D. Because they can do exercise there.

3. The largest mall in the United States ____.

    A. was built in 1965

    B. has 12,750 cars in it

    C. has 350 shops in it

    D. can hold 750,000 people

4. People can do many things in malls except ____.

    A. eating food

    B. seeing a film

    C. seeing a doctor

    D. playing golf

5. The writer ____.

    A. thinks malls make people's life easier

    B. likes to live in his favorite malls

    C. is called "mall rats" by others

    D. ten goes to the church in malls

关于体育锻炼对儿童体格发育影响的叙述，错误的是（）

A.在适当的营养保证下，体育锻炼能提高体格发育水平

B.锻炼时所消耗的能量，锻炼后会加倍得以恢复

C.儿童的跑、跳运动对骨发育有促进作用

D.体育锻炼能促进消化、吸收功能

E."三浴"锻炼可作为学龄儿童增强体质、促进体格发育的主要措施

层高2.20m的有围护结构的架空走廊，其建筑面积（）计算。

A．按走廊的外围水平面积

B．不

C．按走廊的投影面积

D．按走廊的外围水平面积的一半

孟德尔选取豌豆作为他的实验材料，因为它是一种性状的一年生植物。( )