imperfect subjunctive triggers

Question 1

she was very impressed that you had taken dance classes

Answer 1

Le impresionó mucho que hubieras tomado clases de baile

Question 2

I didn’t know anyone who worked at that company

Answer 2

no conocía a nadie que trabajara en esa compañía

Question 3

I wanted you to buy flowers for my birthday

Answer 3

quería que compraras flores para mi cumpleaños

Question 4

I doubt it was as cold as you said

Answer 4

dudo que hiciera tanto frío como dijiste