Not as good as: A 不如 B
比较句 / comparison
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
A + 不如 + B (+ Adj)
A 不如 B (bùrú) = "A is not as good as B, A is less… than B". On its own, it means B is better: 我的中文不如他 (my Chinese isn't as good as his).
You can specify the aspect with a positive adjective: 这个学校不如那个学校大.
不如 is also used for suggestions: 我们不如走路去吧 (we'd better walk).
Examples
我的数学成绩不如我姐姐。
Wǒ de shùxué chéngjì bùrú wǒ jiějie.My maths grades aren't as good as my sister's.
这所大学不如那所大学有名。
Zhè suǒ dàxué bùrú nà suǒ dàxué yǒumíng.This university isn't as famous as that one.
在家复习不如去图书馆。
Zài jiā fùxí bùrú qù túshūguǎn.Studying at home isn't as good as going to the library.
Common mistakes
✗ 这个不如那个小。 → with 不如, use a positive adjective (big, good, pretty…). ✓ 这个不如那个大。
✗ 我不如他很高。 → no degree adverb. ✓ 我不如他高。