Past simple or present perfect?

Since the forest fire, we ________ about climate change at school.

• talked

• have talked

Our government ___________ the use of plastic bottles yet.

• didn't ban

• hasn't banned

I ________ about the use of fossil fuels last year.

• read

• have read

_________ Bruno Mars perform?

• Did you ever see

• Have you ever seen

He (a)   (never/speak) to environmental activists.

We (a)   (watch) an interesting wildlife programme last night.

Our class (a)   (not learn) about recycling yet.

My friends (a)   (not go) to the concert last weekend.

These floods (a)   (already / cause) many problems.

My friends ______________ to a demonstration last week.

• went

• have gone