определите в них видовременные формы глаголов и укажите их инфинитив. The first electronic machines appeared in 1945 in America.
We are prevent and detect crime.

In 1980 the best sportsman from five continents met in Moscow.Practical work is an essential part of University education.Last year my friend headed the research work at the Institute.A group of foreign students will arrive at our city in five days. помоги ещё я английский вобще не знаю

the past indefenite, to appearethe present indefenite, to  prevent, to detect