[Grammar] past continuous modals

[atabitaraf]

1. You should do s.th, (modals in simple present tense)
2. You should have done s.th, (modals in simple past tense)
3. You should be doing s.th, (modals in present continuous tense)
4. You should have been doing s.th, (modals in past continuous tense)
I doubt about the rule and the use of the above sentences. Did I write them on correct formats? And are they useful in your speaking too?
Thanks,

 

[emsr2d2]

They're all fine and are commonly used

 

[5jj]

As emsr2d2 said, your constructions are fine; however, your labelling isn't. Modals do not have continuous forms.

#1 has a modal followed by an infinitive.
#2 has a modal followed by a perfect infinitive.
#3 has a modal followed by a present progressive( or: continuous) infinitive.
#4 has a modal followed by a perfect progressive infinitive.