小红在显微镜下观察青菜叶片的徒手切片，当转动细准焦螺旋时，发现有一部分细胞看得清

加工贸易银行保证金台账实施分类管理，（）应当执行“半实转”。

A．北京A类企业进口限制类商品

B．天津B类企业进口限制类商品

C．上海B类企业进口允许类商品

D．重庆C类企业进口允许类商品

WASHINGTON—Laura Straub is a very worried woman. Her job is to find families for foreign teenagers who expect to live with American families in the summer.

It is not easy, even desperate.

“We have many children left to place—40 out of 75,” said Straub, who works for a foreign exchange programme called LEC.

When foreign exchange programmes started 50 years ago, more families were accommodating. For one thing, more mothers stayed at home. But now, increasing numbers of women work outside the home. Exchange-student programmes have struggled in recent years to sign up host families for the 30, 000 teenagers who come from abroad every year to spend an academic year in the United States, as well as the thousands more who take part in summer programmes.

School systems in many parts of the U.S., unhappy about accepting non-taxpaying students, have also strictly limited the number of exchange students they accept. At the same time, the idea of hosting foreign students is becoming less exotic(有异国情调的).

In search for host families, who usually receive no pay, exchange programmes are increasingly broadening their requests to include everyone from young couples to the retired.

“We are open to many different types of families,” said Vickie Weiner, eastern regional director for ASSE, a 25-year-old programme that sends about 30,000 teenagers on academic-year exchange programmes worldwide.

For elderly people, exchange students “keep us young—they really do”, said Jen Foster, who is hosting 16-year-old Nina Post from Denmark.

小题1:According to the text, why was it easier for Laura Straub to find American families for foreign students?

A．American school systems were better than now.

B．The government was happy because it could gain tax.

C．Foreign students paid hosting families a lot of money.

D．More mothers didn’t work outside and could look after children.小题2:To deal with the problem in recent years, exchange programmes have to ______.

A．extend the range of host families

B．limit the number of the exchange students

C．borrow much money to pay for the costs

D．make hosting foreign students more exotic小题3:Which of the following is the best title of this passage?

A Exchange Students Keep Old People Young.

B. Idea of Hosting Students is Different.

C. Foreign-exchange Program Is Going on.

D U.S. Struggle to Find host Families.

职业性有害因素对胚胎发育的影响，不包括（）

A.胚胎死亡

B.生长迟缓

C.性别异常

D.功能不全

E.畸形

下列有关光合作用的叙述中，不正确的是（　　）

A．光合作用是生物生存、繁荣的基础

B．光合作用为动物和人类提供食物和能量

C．光合作用在植物的所有细胞中都能进行

D．光合作用需要光和叶绿体

妇科疾病是发病机理，可概括为（）

A.先天肾气不足，后天房劳多产损伤肾精，肾虚，冲任不固

B.脏腑功能失常、气血失调、直接损伤胞宫影响冲任为病

C.抑郁愤怒，肝郁气滞，气滞血瘀，冲任失畅

D.忧思劳倦，饮食不节，损伤脾气，冲任不固，气随血陷，脾失统摄

E.忧愁思虑，心阴暗耗，营血不足，冲任虚损