1. …the longest street in the world: 世界上最长的街道。
这是最高级的表达方法，用the加形容词的最高级形式。

类似的例子如：
the longest river in China
the tallest building in my city
the best picture that I have ever seen
the best reason for the success of the program

2. This is because the television program can now be seen in so many parts of the world.: 这是因为现在世界很多地方都能看到这个节目。

"this (that) is because..."常用来引出一个原因。如：
People are spending more time and money on sports. This is because they have realized the importance of sports in their lives.
Generation gap (代沟) is quite common nowadays. This is (partly) because children and parents fail to communicate with each other.
代沟在目前很普遍。这部分由于孩子和家长间缺乏交流造成的。

3. one of America's exports: 美国的出口产品之一

one of表示"……之一"，后面要接名词的复数形式。如：
one of my brothers
one of the developing countries
one of the reasons for the success of the program

4. soon after 不久以后

He got married soon after he left university.

5. although 虽然…但（从属连词）

She was an experienced teacher although she was only 20 years old.

6. agree to: accept or give consent to 同意接受；采用

The workers threatened to strike unless the boss agreed to the terms within 4 hours.
工人们威胁要罢工，除非老板4小时内同意条款。
Cf. agree with: share the same views as (sb.); approval与 …… 一致；同意
What he said did not agree with what he did.
他言行不一。
He agreed to the proposal even though he did not actually agree with it.
虽然他不同意这个建议，但他还是接受了。

agree on: reach an agreement concerning ……达成协议
Through mediation, these two countries agreed on a cease-fire.
通过协商，两国达成停火协议。
At last the two sides agreed on $2 an hour.
最后双方达成协议每小时2美元。

7. Many teachers find that problems appear when the children who have learned from Sesame Street are in the same class with those who have not watched the program.: 很多教师发现如果常看芝麻街的孩子与不常看这一节目的孩子们在同一个班级里上课，就会出现（进度不均）的问题