VOA慢速英语:Introducing English Verb Tenses

aspect – n. the verb form that indicates completion, duration, or repetition of an action.

distinction – n. a difference that you can see, hear, smell, feel, etc: a noticeable difference between things or people

spontaneous – adj. done or said in a natural and often sudden way and without a lot of thought or planning

consciously – adv. done after thinking about facts and reasons carefully

Reference

VERB TENSES
past
present
future
Simple
It snowed yesterday.

Simple past verb
It snows every winter.

Simple present verb
It is going to snow tonight.

It will snow this winter.

Will / be going to + simple present
Progressive
It was snowing when I drove to work.

Was/were + -ing verb
It is snowing.

Am/is/are+-ing verb
It will be snowing by the time I get home.

Will be + -ing verb
Perfect
It had already snowed before I left.

Had + past participle verb
I have driven in snow many times.

Have/has + past participle verb
It will have snowed 6 inches by the end of the day.

Will have + past participle verb

Perfect progressive
It had been snowing for two days before it stopped.

Had been + -ing verb + for/since
It has been snowing all month long.

Has/have + -ing verb + for/since
It will have been snowing for three days by the time it stops.

Will have been + -ing verb + for/since