How do we make the Present Simple Tense?

There are two basic structures for the Present Simple tense:

1. Positive sentences

subject	+	main verb
		Present Simple

2. Negative and question sentences

subject	+	auxiliary do	+	main verb
		conjugated in Present Simple
		do, does		base

Look at these examples with the main verb like:

	subject	auxiliary verb		main verb
+	I, you, we, they			like	coffee.
	He, she, it			likes	coffee.
-	I, you, we, they	do	not	like	coffee.
	He, she, it	does	not	like	coffee.
?	Do	I, you, we, they		like	coffee?
	Does	he, she, it		like	coffee?

From the above table, notice the following points...

For positive sentences:

• There is no auxiliary verb.
• We conjugate the main verb by adding s to the third person singular.

For negative and question sentences:

• The auxiliary verb (do) is conjugated in the Present Simple:do, does
• The main verb is invariable in base form: base
• For negative sentences, we insert not between the auxiliary verb and the main verb.
• For question sentences, we exchange the subject and the auxiliary verb.

Emphatic do
Normally, for positive sentences we do not use the auxiliary verbdo. But if we want to emphasize (stress) something, we may use it. For example, instead of saying "I like your dress", we could say "I do like your dress", just to show how much we like it. Here are some more examples:

• I do wish you'd stop.
• I do apologize.
• You do look smart today.

Present Simple with main verb be

The structure of the Present Simple with the main verb be is:

subject	+	main verb be
		conjugated in Present Simple
		am, are, is

Look at these examples with the main verb be:

	subject	main verb be
+	I	am		French.
	You, we, they	are		French.
	He, she, it	is		French.
-	I	am	not	old.
	You, we, they	are	not	old.
	He, she, it	is	not	old.
?	Am	I		late?
	Are	you, we, they		late?
	Is	he, she, it		late?

From the above table, notice the following points...

• There is no auxiliary verb, even for questions and negatives.
• The main verb (be) is conjugated in the Present Simple: am, are, is
• For negative sentences, we insert not after the main verb.
• For question sentences, we exchange the subject and the main verb.

Source: https://www.englishclub.com