1. Food prices rise sharply in Egypt.

(What is the meaning of 'sharply' here?

2. Sometimes be happy.
3. Be sometimes happy.
4. Be happy sometimes.
(Can we use thises sentences? Which one is common?)

prices rise a lot quickly

4 is all right. 2 and 3 do not sound right.

Damon is right about 2 and 3.

It's the placement of the adverb. In English, they usually are better when placed after the verb. Not always, but usually.

1. The word "sharply" in the context of rising food prices in Egypt means that the increase in prices is significant and sudden. It suggests a rapid and noticeable change rather than a gradual increase.

2. "Sometimes be happy."
This sentence is grammatically correct, but it sounds a bit awkward and is less commonly used compared to the other three options.

3. "Be sometimes happy."
This sentence is not commonly used in English. While it is grammatically correct, the adverb "sometimes" is typically placed before the verb "be" to form a more natural-sounding sentence.

4. "Be happy sometimes."
This sentence is grammatically correct and is a more common way of expressing the idea of occasionally being happy. The adverb "sometimes" is placed before the verb "be," which gives it a more natural flow.

In summary, the most frequently used and natural-sounding sentence is "Be happy sometimes."