酶工程法与直接发酵法生产氨基酸的不同点

The sculptors cannot control the result because ______.

A．it is extremely sunny and warm

B．it shines and/or snows

C．the sun melts their sculptures

D．old sails are raised into the air

The sculptors cannot control the result because ______.

A．it is extremely sunny and warm

B．it shines and/or snows

C．the sun melts their sculptures

D．old sails are raised into the air

The government cannot compromise too much to the teachers unions because ______.

A．the negotiations are ineffective

B．the strike is actually under control

C．it will set an example for other unions

D．the teachers" unions will demand more

A．They cannot sit still or control their actions.

B．They cannot talk fluently.

C．They cannot study well.

D．They cannot express their ideas well.

Frogs are important in the ecosystem because they control pests.

A．Y

B．N

C．NG

______ are bound morphemes because they cannot be used as separate words.

A．Roots

B．Stems

C．Affixes

D．Compounds

Does Peggy care about the noise in Woodside Road？

A．Yes, because she cannot sleep well.

B．Yes, because she cannot concentrate on her study.

C．No, because she would be out all day.

D．No, because she cannot hear it.

A．Incentive （激励）

B．Exchange （交换）

C．Counter （柜台）

D．Payment （支付）

charge for an apartment. Supporters of rent control argue that it protects people who are living in apartments. Their rent cannot increase; therefore, they are not in danger of losing their homes. However, the critics say that after a long time, rent control may have negative effects. Landlords know that they cannot increase their profits. Therefore, they invest in other businesses where they can increase their profits. They do not invest in new buildings which would also be rent-controlled. As a result, new apartments are not built. Many people who need apartments cannot find any. According to the critics, the end result of rent control is a shortage of apartments in the city.

Some theorists argue that the minimum wage law can cause problems in the same way. The federal government sets the minimum that an employer must pay workers. The minimum helps people who generally look for unskilled, low-paying jobs. However, if the minimum is high, employers may hire fewer workers. They will replace workers with machinery. The price, Which is the wage that employers must pay, increases. Therefore, other things being equal, the number of workers that employers want decreases. Thus, critics claim, an increase in the minimum wage may cause unemployment. Some poor people may find themselves without jobs instead of with jobs at the minimum wage.

Supporters of the minimum wage say that it helps people keep their dignity. Because of the law, workers cannot sell their services for less than the minimum. Furthermore, employers cannot force workers to accept jobs at unfair wages.

Economic theory predicts the results of economic decisions such as decisions about farm production, rent control, and the minimum wage. The predictions may be correct only if "other things are equal". Economists do not agree on some of the predictions. They also do not agree on the value of different decisions. Some economists support a particular decision while others criticize it. Economists do agree, however, that there are no simple answers to economic questions.

There is the possibility that setting maximum rent may ______.

A．cause a shortage of apartments

B．worry those who rent apartments as homes

C．increase the profits of landlords

D．encourage landlords to invest in building apartment

A．Because

B．Because of

C．As a result

D．Considering