Sentences:

1. Approval: Happiness is the innocent smiling faces of children, and happiness is the approving eyes of teachers.

2. Praise: Walking on the tree-lined road is not worthy of praise. Climbing dangerous peaks is the real pleasure.

3. Praise: If the first book review is bad, the author needs at least three praises from the review to change people's first impression.

4. Praise: His good conduct was praised by people.

Difference: Both mean to express praise. There are slight differences in usage. Like is mostly used as adverbs or nouns; praise, praise, and praise are mostly used as verbs or nouns.

Expansion: The main differences between synonyms are:

(1) The degree of meaning: Many synonyms represent similar things in concept, but there are differences in degree. Such as: "trust", "believe". "Believe" means "thinking it is correct or convinced without doubting it", which is a lighter degree; "trust" means "believing and daring to trust", which is a deeper degree.

(2) The focus of the word meaning: "Sophistry" and "sophistry" both mean "unreasonable argument". But sophistry focuses on "cunning", that is, "deception, weirdness, using deceptive means, strange words, and specious arguments to defend one's fallacies"; "sophistry" focuses on "cunning", that is, "dishonesty, playing tricks" , distorting facts and cunningly defending his wrong words and deeds."

(3) The scope of the word’s meaning: “reclamation”, “opening up” and “opening up” all have the meaning of “development”. However, "reclamation" refers to "employing efforts to develop barren land into cultivated land", and "exploitation" refers to "expanding on the basis of original development". The scope of their meanings is relatively small; "opening up" mainly refers to "new Development, new creation" has a wide range of meanings.

(4) Objects used by word meanings: Although some words have similar meanings, they are suitable for different objects and situations. "Appreciate" and "understand" both mean "understanding, experiencing, knowing". But the former focuses on emotional experience and appreciation, which can be connected with "flavor", "scenery", etc.; while the latter focuses on rational understanding and understanding, which is applicable to abstract things and can be connected with "content", "principle", etc.