Explain the use of the articles with “plant” in the highlighted paragraph in Ex. 2B,p.90 above. • In which cases do we

A plant - meaning “any plant will do”

A second plant - any other plant

This second plant - we have already a determiner “this” here; otherwise it might be “the”, as the speaker means a particular plant, the one mentioned before.

The fist plant - the speaker means a particular plant, the one mentioned before.

The two plants - the ones mentioned before in the paragraph.