基本句子结构：
S + LV + SC ( 主语 + 系动词 + 主语补足语 )
常见系动词有： be, seem, appear, look, remain, sound, feel, smell, taste, become, grow, turn, go, prove, etc.

S + LV + N ( 主语 + 系动词 + 名词 )

1. _____________________ is one of man’s greatest ___________________.
生物多元化是人类最大的财富。

2. ____________________________ of the Internet is an appropriate ________________ of the government.
对互联网的立法管理是政府的职能。

3. The legalization of marijuana ____________________________ in our community.
大麻合法化在我们社区成了个焦点话题。

4. The greatest contribution of ____________ is the healthy attitude to life it encourages.
男女共校制度的最大优点是它所提倡的健康的人生态度。

5. One merit of the Internet is ___________________ the latest information.
互联网的好处是能迅速方便地获取最新的资讯。

答案：
1. Biodiversity, assets
2. Legislative¹ regulation, function
3. has become a hot-button issue
4. coeducation
5. easy access to