Answer:
1. Diane is not as young as I am.
2. My composition is not as good as yours.
3. Tim is not as intelligent as Sandra.
4. I don't have as many cousins as you.
5. Spain is as hot as Portugal.
6. Tim did not get as many points on the test as Liz.
Explanation:
We use "as... as" to compare people or things. If used in an affirmative sentence, "as... as" will convey that both elements beings compared are at the same level concerning the attribute being mentioned. If used in a negative sentence, it will convey the elements are not equal.
Among the sentences in the question, only number 5 states that both elements are at the same level. It is also important to note that numbers 4 and 6 ended up using "as many... as" since they are not comparing adjectives, but countable nouns (cousins and points).