Can you give me a sentence that the simple subject also is the complete subject in it

Such a sentence could have a person's name; the second word would be the verb; and the third and further words would be the direct object and/or other parts of the predicate.

See the first two examples here:

http://www.uottawa.ca/academic/arts/writcent/hypergrammar/bldsent.html

Certainly! Here's a sentence where the simple subject is also the complete subject:

"The dog barked loudly."

In this sentence, the simple subject is "dog" because it is the noun that is performing the action (barking). Moreover, "dog" also forms the complete subject because it includes any modifiers or articles directly associated with it.