题目内容：

A PG-13 rating is a stricter warning by the Rating Board to parents to determine whether their children under age 13 should view the film. A PG-13 film may go beyond the PG rating in theme, violence, nudity (裸露), language, adult activities or other elements, but does not reach the restricted R category.

The theme of the film by itself will not result in a rating greater than PG-13, although activities shown in the film related to a mature theme may result in a restricted rating for the film. Any drug use will initially require at least a PG-13 rating. More than brief nudity will require at least a PG-13 rating, but such nudity in PG-13 rated film generally will not be sexually oriented. There may be violence scene in a PG-13 movie, but generally not both realistic and extreme or persistent violence.

A single use of one of the rude words in a film, though only as an expletive (感叹语), initially requires at least a PG-13 rating. More than one such bad word requires an R rating, as must even one of those words used in a sexual context. The Rating Board nevertheless may rate such a film PG-13 if, based on a special vote by a two-thirds majority, the Raters feel that most American parents would believe that a PG-13 rating is appropriate because of the context or manner in which the words are used or because the use of those words in the film is easily neglected.

1.What is the main goal of this passage?

A.To discuss various movie ratings.

B.To explain various movie ratings.

C.To explain the difference between PG-13 and R movie ratings.

D.To explain the PG-13 movie rating.

2.According to PG-13 rating, the theme of the movie __________.

A.has little impact on its rating

B.has a large impact on its rating

C.should be entertaining

D.should be suitable for children

3.From Paragraph 2, we can learn that drug usage __________.

A.should not be allowed in movies

B.is dangerous

C.makes a PG-13 rating necessary

D.is not appropriate for children under 13

4.What does a movie with two or more uses of bad words require?

A.A PG rating. B.A PG-13 rating.

C.An R rating. D.An NC-17 rating.