What tense are these TIME MARKERS used with?
What TENSE do these structures refer to?
EXCEPTIONS AND PARTICULAR CONSTRUCTIONS
100

While/when    

Past continuous

100

Subject + simple past of “TO HAVE” + past participle   

Subject + HADN’T + past participle

HAD + subject + past participle?

Past perfect

100

What conditional refers to unreal or imaginary situations in the present or in the future?

Second conditional or if-clause type 2

200

After/before/by the time…

Past perfect

200

Subject + WOULD HAVE + past participle

Where do you use it?

Perfect conditional       

It is used in third conditionals

200

When do you separate the main clause and the if-clause with a comma?

When the if-clause goes BEFORE the main clause

300

Perhaps / Maybe    

Future Simple

300

Where can you use both the simple present and the imperative in the main clause?

In zero conditionals.

400

What form of the verb “to be” do you use in second conditionals?

Were (for all people)

500

What conditional refers to unreal or imaginary situations in the past?

Third conditional or if-clause type 3