1. Subject – Verb Agreement

Third person singular -s

That man live in California. (wrong)
That man lives in California. (correct)

2. Wrong tense

Watch for key “time words” and phrases

Yesterday I go to the dance. (wrong)
Yesterday I went to the dance. (correct)

Extra “be”

What was happened last night? (wrong)
What happened last night? (correct)

Omitted “be”

I concerned about my grades. (wrong)
I am concerned about my grades. (correct)

Insertion of “to”

I had better to go. (wrong)
I had better go. (correct)

Non-base form after modal

I could played basketball. (wrong)
I could play basketball. (correct)

5. Wrong word choice

I have met Johanna for five years. (wrong)
I have known Johanna for five years. (correct)