maybe or may be.

[ming]

Dear teacher.

Please explain these words to me.
I can do these following sentences correctly. But I don't still undestand.
Please help.
1. What he said may be true.
2. These shoes may be Alice's.
3. Susan is late maybe she's sick.
4. This test may be long, but it is not difficult.

All your best.
Thanks.

[Pete]

Dear teacher.

Please explain these words to me.
I can do these following sentences correctly. But I don't still undestand.
Please help.
1. What he said may be true.
2. These shoes may be Alice's.
3. Susan is late maybe she's sick.
4. This test may be long, but it is not difficult.

All your best.
Thanks.
I think the best way to think of it is to note that "may be" is a verb (one using the modal auxiliary "may" and the infinitive "be"). On the other hand, "maybe" is an adverb, not a verb. In the sentences that used "may be", there was a subject for the verb "may be":
1. What he said may be …
2. … shoes may be …
4. … test may be …

Sentence 3 needs a semicolon:
3. Susan is late; maybe she's sick.
There are already verbs for the subjects: Susan is …. She's …. In this sentence, "maybe" isn't a verb; it is an adverb modifying the whole second clause. Thus you use the adverb "maybe", not the verb "may be".

[ming]

Dear Pete,
your explanation is clear.
Thanks a lot.