A. Simple present = base form: I work. OR base form + -s: He works. She works. It works. OR base form + -es : I watch / she watches; I study / he studies
1. A general truth.
The sky is blue.
2. A typical activity.
I always brush after I eat.
Bob watches TV every night.
Sara works 5 days a week.
3. A statement of something existing at the time of speaking.
I hear the train coming.
I smell smoke.
4. A scheduled event or activity.
My plane leaves at 8:30 tomorrow.
B. Simple past = base form + -ed for regular verbs : I worked yesterday. The simple past for irregular verbs varies : He ate lunch at noon. (irregular verb)
1. An activity begun and completed at a particular time in the past.
I went to work yesterday morning.
2. Commonly used with "after" and "before" clauses.
After Bob ate dinner, he drove to CEC.
The students arrived in class before the teacher.
3. "Used to" = past habits (used to + base form)
I used to ride horses when I was a kid.
C. Simple future = will + base form: I will work tomorrow. He will eat dinner later. OR am / is / are + (going to + base form): I am going to work tomorrow. She is going to eat dinner at Al's Restaurant. We are going to study Unit 1 tonight.
1. A future event or activity.
Our break will begin at 8:10.
I will study later.
I'm going to study later.
2. Use will (not: going to) to volunteer.
A. Wait a second. I will help you with that sofa. If you try to move it by yourself, your back will be out for a week.
3. Use going to (not: will) with a preconceived plan.
I'm going to mow my lawn tomorrow.
D. Present perfect = have + past participle : I have worked. I have eaten. OR has + past participle: She has worked. She has eaten.
1. An activity that began in the past and continues into the present , often using "since, " "since...ago," or "for":
"since" = a particular time: I have / She has studied English since 1997.
"since...ago" = a particular time: I've / She's studied English since 5 years ago.
"for" = a duration of time: I've / She's studied English for 5 years.
2. A repeated activity.
I have / He has gone to ESL class every day this week.
3. An activity that occurred at an unspecified time in the past.
A. Have you ever visited New York? B. No, but I have visited New Orleans.
4. An activity in a time clause (e.g., when..., while..., after...) that ends before the main clause activity begins.
I will go to the movie after I have studied Unit 1.
E. Past perfect = had + past participle : I had worked. She had eaten.
An activity in the past that ended before another activity in the past.
e.g. They had already gone to Lab by the time I arrived.
F. Future perfect = will have + past participle : I will have worked. She will have eaten.
An activity in the future that will end before another activity in the future.
e.g. They will have left Lab by the time I arrive.