What do you do in the evening?

1. I do house chores from time to time.
2. I do household chores from time to time.
3. I do chores from time to time.
4. I do some chores from time to time.
5. I do housework from time to time.
[Are they all grammatical? Which ones are common expressions?]

6. I go to an academy to learn three subjects.
7. I go to a private institute to learn three subjects.
8. I go to a private institution to learn three subjects.
9. I go to a private academy to learn three subjects.
[There seem to be several expressions for "academy" to learn more after school. Are the expressions here all acceptable? Which expressions would you like to recommend? Thank you. I appreciate your help.]

2 - 5 are all correct. 1 is not.

6 - 9 are all well written. You can use any of them for the purpose you gave. Nice!!

Regarding the first set of sentences:

1. "I do house chores from time to time." - Grammatically correct and commonly used.
2. "I do household chores from time to time." - Grammatically correct and commonly used.
3. "I do chores from time to time." - Grammatically correct, but not as specific as the previous two options.
4. "I do some chores from time to time." - Grammatically correct, but the use of "some" makes it less specific.
5. "I do housework from time to time." - Grammatically correct and commonly used.

Regarding the second set of sentences:
6. "I go to an academy to learn three subjects." - Grammatically correct and acceptable.
7. "I go to a private institute to learn three subjects." - Grammatically correct and acceptable.
8. "I go to a private institution to learn three subjects." - Grammatically correct and acceptable.
9. "I go to a private academy to learn three subjects." - Grammatically correct and acceptable.

All of the expressions for "academy" to learn more after school are acceptable. The choice of which expression to use depends on personal preference and cultural context. In general, "academy" and "institute" are commonly used, while "institution" may sound more formal or official. "Private" is used to specify that it is not a public or government-run facility.

Ultimately, the decision on which expressions to recommend would depend on the specific context, audience, and cultural norms. It is always a good idea to choose the expression that best fits the intended meaning and conveys it clearly.