The twins are so much______that it is difficult to tell one

A. load

B. loaded

C. loading

D. to load

The twins are so much that _________it is difficult to tell one from the other.

A． same

B． likely

C． alike

D． identical

There are two types of twins: identical and non-identical twins. Identical twins are formed from a single egg in mother's body which divides to form. two separate babies. Identical twins look the same and are often dressed by their parents in clothes of the same colors. It is often difficult to tell identical twins from each other, even when they are standing side by side. Non-identical twins come into being when the mother produces two separated eggs at the same time, both of which grow to form. babies. In this case the twins look like normal brothers and sisters and are easy to tell one from the other.

In the 1970s and 1980s a scientist did some research into twins. He invited many pairs of identical twins to university and asked them to take part in a week of tests. He was particularly interested in adopted (收养) twins who had been separated at birth. He would give the twins different kinds of tests to study their speed of thinking, their speech, their memory, the ways they saw and heard different things, and so on. Time and time again he found separated twins who preferred clothes of the same color, used the same kind of shaving soap, wore the same shaped square glasses and the same colored socks.

There is a third type of twins, but it is a very unusual one. Twins who are joined together at birth are known in western countries as Siamese twins.

(1)It is difficult to tell identical twins because ____________.

A、they are dressed in the same clothes

B、they are dressed in the same color

C、they are very alike

D、they are standing side by side

(2)If the twins are easy to tell from each other, they are ____________.

A、very probably non-identical twins

B、surely non-identical twins

C、surely identical twins

D、always a brother and a sister

(3)Which of the following is NOT true according to this passage?

A、In the 1970s and 1980s a scientist did some research into the two main types of twins.

B、In the week of tests, he tested their speed of thinking, their speech, their memory and some other things.

C、There were twins who had been separated from each other as soon as they were born.

D、Very often, separated twins were found to choose things of the same kind, the same shape and the same color.

(4)According to the passage, how many types of twins are there actually?

A、one

B、two

C、three

D、four

(5)This passage mainly tells us ____________.

A、the main types of twins

B、what has been found out about twins

C、how twins are formed

D、how a scientist studied twins

To most of the students, Economics ( )always an important subject, also a difficult one.

A、is

B、are

C、have been

D、was

A

This is the twins' bedroom． It is a nice room． The two beds look the same．This bed is Lily's and that one is Lucy's． The-twins have two chairs and one desk． Their clock， books and pencil cases are on the desk． Their backpacks are behind the chairs Some nice flowers(花) are on the desk． Some pictures are on the wall． Is there a base-ball? Yes， it，s under Lily's bed． The bedroom is very nice．

( )21． The twins are ________ ．

A． at home

B． have a nice room

C． in different room

D． in the same room

A. a

B. an

C. the

D. one

What is the 'biggest city in the world? That is, (21) city has the largest population? This seems like (22) question to answer, but actually it isn't.

It's actually rather difficult to say which cities (23) the largest. There are two reasons for this difficulty. First of all, it isn't easy to determine a city's boundaries, that is, where a city ends. Nowadays, nearly all cities have a large (24) area around them. So when we talk about the population of a city, we often mean the population of the whole metropolitan area around the city. That means that it's difficult to determine what the population of a city is because it's difficult to define what a city is.

The second reason that it is difficult to 25 the population of different cities is this: it is almost impossible to get (26) about the population of all cities for the same year. For example, we might get an estimate of New York's population in 1979 and an (27) of Mexico City's population in 1981. So we real ly can't compare the numbers because the information is for (28) different years. And the population of cities changes rather quickly, especially in some cases. For example, the population of Jakarta, Indonesia, may increase by 5% each year, so the population figure will change rather quickly.

So we can say that these are our two (29) for comparing the populations of cities: one, it's difficult to determine the (30) of a city, and two, it is difficult to get accurate information.

21. A. what

B. which

C. where

D. how

A、So does the one.

B、So the one does.

C、The one does so.

D、The one so does

One of the African guides could tell that these nests had been abandoned by the gorillas long before.()

It is not always so easy to tell the true ______ the false.

A、between

B、instead of

C、from

D、against