We would never have expected that.
What do I mean by that?
The Moscow underground transportation system is the deepest one in the world.
If you don't use it anymore for 10 years or longer, you will not forget it.
I'm only scratching the surface here.
Being a bilingual was really helpful in learning my first language.
You have to listen carefully and you repeat.
PAST MODAL
PRESENT SIMPLE
MODAL FOR OBLIGATION
SUPERLATIVE FORM
FIRST CONDITIONAL (Present Real Conditional)
GERUND
PRESENT CONTINUOUS