若x=12是方程3-x=a-3x的解，则a=（ ） A．2 B．52 C．4 D．6

Bananas don’t grow on trees. They grow on a stalk that looks just a little like a stalk of corn. The stalk is soft enough to be cut with a knife.

It takes about a year before bananas are ready to be picked. Some are as small as fingers. Others are as long as men’s arms. Some banana plants grow as tall as a house – even taller!

Not all bananas are eaten as fruit. Some never get sweet, and they are cooked as a kind of vegetable.

People in most countries never see a banana until it reaches the store. But if you visited a country where it’s hot and rains a lot all the year, you might see a banana plantation, a large farm where bananas grow.

The tasty fruit doesn’t come from a seed but from a root planted deep in the ground. First a stalk pushes up into the air. The leaves grow. In the beginning the banana plant grows very fast – sometimes as much as the length of your feet in one night. Soon, sweet-smelling flowers come out, and when their flowers drop off, bananas begin to grow.

As they get bigger, bananas start turning up. It looks as if they’re growing upside down! Bananas are ready to eat when they turn soft and yellow. Bananas are picked long before this – when they’re hard and green. This is because bananas have to travel many miles before they arrive at a store. On trucks and boats and trains bananas travel all over the world. There are special boats just for bananas and special trains that keep them just cool enough so that they will get ripe while traveling. If bananas are picked when they are ripe (成熟的), they will spoil on the way.

小题1:What’s the weather like in places where bananas grow?

A．Dry and cold

B．Cold and wet

C．Wet and hot

D．Hot and dry小题2:The fruit of banana plants come from________.

A．a stalk

B．a tree

C．a seed

D． a root小题3:Bananas are picked long before they are _____________.

A．green

B．ripe

C．hard

D．red小题4:Which of the following is NOT true according to the passage?

A．All bananas are eaten as fruit.

B．Some banana plants grow taller than a house.

C．Bananas get ripe on their way to the store.

D．It takes about a year before bananas are ready to be picked.

设X1，…，X是取自总体X的容量为n的样本，总体均值E（X）=μ未知，μ的无偏估计是（）．

A.

B.

C.

D.

动脉粥样硬化主要危险因素有（）。

A.血脂异常

B.吸烟

C.糖尿病和糖耐量异常

D.血压

E.年龄、性别

下列诸因素中，对计算机的正常工作影响最小的是

A．湿度

B．温度

C．尘土

D．噪声

近代以来世界市场的形成和不断扩大，推动着世界经济的发展和人类社会的进步。

材料一：所谓的商业革命，欧洲的商人和殖民者在欧亚非美之间建立了直接的商业联系……初步形成了一个广阔的世界市场；欧洲的商路和贸易中心随之由地中海转移到大西洋沿岸，意大利的商业垄断地位逐渐被葡萄牙西班牙尼德兰英国所取代。

——孔祥民主编《世界中古史》

材料二：火车、轮船、电报等新式交通工具和电讯器材的出现，把世界各地的生产、流通和消费紧紧联结在一起。1869年苏伊士运河开通，使欧洲到印度的航路缩短了4000英里。1914年峻工的巴拿马运河则使旧金山到利物浦的航程近了5666英里。轮船的不断更新，使航速大大提高，欧美航程从42天缩短为5天，从伦敦到加尔各答也由3个月减为18天。此外跨洲铁路的修筑，加强了洲际联系。有线电报、电话和无线电报的普及，使世界通讯网络得以形成。

——斯塔夫里阿诺斯《全球通史》

材料三：经济全球化是近年国际问题中的热门话题，专家认为：“严格意义上的经济全球化发生在80年代末90年代初。全球化之所以发生在这个时期，第一靠全球的信息网络化，第二靠全球向市场化的变革。前者为全球化提供了技术的保障，后者为全球化提供了机制上的保障。”

——陈宝森《经济全球化进程刚刚开始》

面对全球化趋势，中国政府采取了哪些应对措施？