Which categories of goods are excludable？（）

单项选择题Domestic oil（）and gasoline prices are two important issues in the presidential campaign.

A.exploration
B.explored
C.exploring
D.explore

单项选择题Vietnam has（）as the world’s third-biggest rice exporter.

A.emerged
B.merged
C.occurred
D.happened

单项选择题Mr.Leach is on holiday and was not（）for comment.

A.amazed
B.available
C.annoyed
D.anticipate

单项选择题（）that dieting is fruitless for people who think that they are too fat，the alternatives are fairly limited.

A.Assuming
B.Assumed
C.Assume
D.Assembled

单项选择题Which of the following involves using the inherent strength of social networks to encourage visitors and fans to share their Likes and comments with friends？（）

A.social density
B.engagement
C.amplification
D.dark social

单项选择题Which of the following is a good definition？（）

A.A party is where you go to have a good time.
B.Democracy is a system of government in which every citizen in the country can vote to elect its government officials.
C.An astronomer is one who studies astronomy.
D.Pollution is the process that chemicals are dumped into rivers.

单项选择题Do you mean to risk（）cold by going out now that it has started pouring with rain？

A.catch
B.to catch
C.catching
D.caught

单项选择题（）once said that the most beautiful things in our world are created by Labor，by the wise hands of human being.

A.Gorky
B.Marx
C.Tolstoy
D.Hugo

单项选择题One of them threatened me with a knife（）the other bound and gagged me.

A.if
B.although
C.while

单项选择题Which of the following is not the feature of a good topic？（）

A.Feasible
B.Wide-ranging
C.Original
D.Scientific