I sit on the bench by the lake, составить это предложение в временах; Pr. Cont, Pr. Perf, Past Cont, Past Simple и в Past Perf.

I sit on the bench by the lake
I am sitting on the bench by the lake - Present Cont.
I have sat on the bench by the lake - Present Perfect
I was sitting on the bench by the lake - Past Cont.
I sat on the bench by the lake - Past Simple
I had sat on the bench by the lake - Past Perfect