"Sing" is the usual form of the present tense.
For example " We sing".
The exception is the "third person singular" which is "sings", as in "She sings".
it is a present because it is like singing.
The present tense of the word "sing" is "sings."
Have is already present tense.
It is a continuous form of the present tense. "He plays football."
* I am * you/we/they are * he/she/it is
The present tense is sing and sings.The past tense is sang.The future tense is will sing.The present participle is singing and the past participle is sung.
Past tense: Shone Present tense: Shining Future tense: Will Shine
I/you/we/they look. He/she/it looks. The present participle is looking.
"You" is not a verb nor an action, and does not have a present, past, or future tense form.
'Takes' is used in the present tense when using the subjects he, she or it.
To "maintain" would be in the present tense. "Maintained" would be the past form.
The word "contains" is in the present tense. It is the third person singular form of the verb "contain".