There goes their work on that science project!
A sentence to say in one sentence is to say a sentence in one sentence! It is quite easy to say a sentence in one sentence if that is all you have to say. "The cat with brown hair, hair of brown has the cat" is a sentence to say in one sentence. To say in one sentence the reasons behind the onset of World War Two does not do the subject any justice at all.
A single sentence is one sentence.
A simplistic sentence is a sentence that contains one action and one noun. "I ran." Is and example for a simplistic sentence.
"I have a sentence for you."
As a question, it can be a sentence, like: A sentence can have one word, and as a question then it can be a sentence: Who?
a descriptive sentence is a sentence that describes something in one sentence
A sentence can have just one word, so "No." can be a sentence.
Complex (APEX)
In a sentence. "For example this a a sentence."
A thesis statement is typically one or two sentences that summarize the main point or claim of an essay. While it is traditionally structured as a single sentence, it can sometimes be extended into two sentences if necessary to clearly articulate the writer's argument.
a sentence.
one sentence for past