when writing it like that, you need to put "ing" after the verb. For example- kevin is work(ing) in the hospital, he is operat(ing) on people.

Kevin works in a hospital. He operates on people. Works and operates are the third person singular (he, she, it) form for the present simple tense. We use the present simple tense when we talk about permanent states, habits, routines etc. Kevin works in a hospital= that is his permanent place of work. Kevin operates on people = that is what he does in his job. Kevin is working in a hospital. He is operating on people. 'Is working' and 'is operating' are the third person singular form for the present continuous tense. We use the present continuous tense when we talk about actions in progress now, temporary states/ actions and definite future arrangements/appointments. Kevin is working in a hospital at the moment = now Kevin is at the hospital working. Kevin is working in a hospital this week = This week (not necessarily at the moment the moment of speaking) Next week he may be working somewhere else. (Temporary) Kevin is working in a hospital tomorrow = future. You cannot use 'is' with the base form of the verb. 'is work' and 'is operate' are not correct.

He operates on people = He operated on people in the past, he may be operating on people today and will operate on people in the future (continuous present) He is operating on people = He is operating on someone right now. In spoken English, you will hear people say "He is working at the hospital", when the tense should be "He works at the hospital". Again "He is working at the hospital" = He is at the hospital working there as we speak.

thank you so much

Kevin works in a hospital and operates on people.