Khan Academy
Khan Academy: Introduction to Verb Aspect
If verb tense allows you to control the past, the present, and the future, then aspect gives you even finer control over time. David, Khan Academy's resident grammarian, explains.
Khan Academy
Khan Academy: Introduction to Verb Tense
An understanding of verb tense will make you into a TIME WIZARD, with the ability to control the past, the present, and the future - with your words, anyway.
Sophia Learning
Sophia: The Simple Present: Lesson 4
A screencast [3 mins, 43 secs] explaining and giving examples of simple present tense verbs. It is 4 of 4 in the series titled "The Simple Present."
Sophia Learning
Sophia: The Simple Present: Lesson 1
A tutorial explaining simple present tense. Audio is available [1 min, 6 secs]. It is 1 of 4 in the series titled "The Simple Present."
Sophia Learning
Sophia: Present Perfect: Lesson 4
This lesson introduces the present perfect tense and how it is used. It is 4 of 4 in the series titled "Present Perfect." [5:08]
Sophia Learning
Sophia: Present Perfect
This lesson introduces the present perfect tense and how it is used. This tutorial lesson shares a short screencast [3:57] with the lesson's content.