I was thinking of flying to London next week, but I'm going to travel by train instead.

I'm thinking of flying to London next week, but I'm going to travel by train instead.

I have been thinking of flying to London next week, but I'm going to travel by train instead.

Pollution is continuing to damage our planet for many years to come.

Pollution will continue to damage our planet for many years to come.

Pollution will have continued to damage our planet for many years to come.

We have so many empty bottles that I think I'll take them to be recycled this afternoon.

We have so many empty bottles that I think I'm taking them to be recycled this afternoon.

We have so many empty bottles that I think I'll have taken them to be recycled this afternoon.

If we continue to burn fossil fuels, Greenland's ice sheet will be melting by 2050.

If we continue to burn fossil fuels, Greenland's ice sheet is melting by 2050.

If we continue to burn fossil fuels, Greenland's ice sheet will have melted by 2050.

We will only recognise that there is a problem when resources will run out.

We will only recognise that there is a problem when resources will be running out.

We will only recognise that there is a problem when resources are running out.

Choose the correct sentence