1. What are the synonyms of delicious?

-They are yummy and tastey.

2. What is the antonym of delicious?
- It is tasteless.
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Q1: Are the questions and answers correct?
Q2: Do you have other common opposites of 'delicious' other than 'tasteless'?

3. Chuchu behaved strangely. He hit against the flowerpot many times. What did the master do for the pet? He took the pet to an animal hospital.
(Would you check the short passage? Thank you.)

For Q1 and Q2:

http://www.thesaurus.com/browse/delicious

Your passage is fine. You might say "his" or "her" pet instead of "the" pet.

Rather than "hit against..." I'd say, "He ran into the flowerpot many times."

A1: Yes, the synonyms of delicious are indeed "yummy" and "tasty."

A2: While "tasteless" is indeed an antonym of "delicious," there are also other common opposites of "delicious" such as "disgusting," "unappetizing," or "unpalatable."

Regarding the short passage you provided, it appears to be grammatically correct. However, there may be room for improvement in terms of clarity and coherence. Here is a revised version:

"Chuchu behaved strangely, repeatedly hitting against the flowerpot. In response, the pet's owner took Chuchu to an animal hospital."

This revised version offers a clearer description of Chuchu's behavior and the owner's action.