5. 解析:选D。考查动词短语辨析。(be) made of/from 由……制成，前者能看出原材料，后者看不出原材料或不明显；(be) made up of 由……组成；(be) made into 被制成……,在句中为分词短语作定语。故答案为D。

4. 解析:选C。考查时态。“This is the first/second/third time + that从句”，意为“是第几次做……”，从句应用现在完成时态。故答案为C。

3. 解析:选D。考查动词词义辨析。句意为：在人类的帮助下，鸟儿们度过了一个极其寒冷的冬季，尽管它们自己没有储存足够的食物。suffer 遭受损失、伤害、损害或惩罚；live 生存；bear 忍受；survive 幸存，艰难渡过，符合句意。故答案为D。

2. 解析:选A。考查短语辨析。句中的被修饰词是parents, 四个选项中修饰可数名词的只有a great many。C、D两项修饰不可数名词；a lot不修饰名词，修饰名词时后需加of ,故答案为A。

5. The price of pork has gone up, but I doubt whether it will remain so.

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4. The American student gave me English lessons in exchange for Chinese lessons.

3. In the zoo, children are not allowed to approach those animals which look safe.

2. This/It is the third time I have told you not to bring your cellphone into the class.

5. have been discovered

4. have visited; came