Can (bisa): meminta pertolongan/mengajak/izin, menyatakan kemampuan, dll.
"Can you give me that book"? "Can you drive me to the museum" "Can I go to the bathromm" "I can kick a ball"
May (mungkin): meminta pertolongan/mengajak/izin, menyatakan kemungkinan, dll.
"May I take you to the prom?" "May I borrow your book?" "You may go to the museum."
Must (harus): mengatakan/menanyakan keharusan, dll.
"You must obey the rules." "Why must they obey the bad laws?"
Should (harus, tidak terlalu formal): mengatakan/menanyakan keharusan, dll.
"You should take your pet to the dentist." "Should I do my homework now?"
Will (akan): meminta pertolongan/mengajak/izin, dll.
"Will you pass me the sauce?" " Will you go out with me?"