Он проработал с нами только месяц,

Он проработал с нами только месяц, но доказал, что он опытный работник

Результаты (английский) 1:

He worked with us only a month, but has shown that he is an experienced worker

Результаты (английский) 2:

He worked with us only a month, but proved that he is an experienced worker

Результаты (английский) 3:

He has worked with us only a month, but it has proved that he was an experienced worker more multitasking performance