This uses the present perfect continuous tense, which is used to describe an action that started in the past and is still continuing in the present.
Explanation: "Off and on" means something that happens at irregular intervals, similar to "occasionally."
The man has 4 sons and one sister shared among them.
Thus, the total number of children is 4 + 1 = 5.
The phrase "one of the highest" correctly indicates.
It shows that the Eiffel Tower is among the tallest man-made structures.
It uses appropriate comparative language.
Saudi Arabia is the world's largest exporter of crude oil.
It is the backbone of its economy.
Saudi Arabia imports machinery and equipment to support industrial growth and infrastructure development.
In negative sentences, "does" is used.
It is followed by the base form of the verb "like."
This makes the sentence grammatically correct.