"If you want to stay healthy, you __________ eat so much junk food."
"If you want to stay healthy, you should - must eat so much junk food."
"She __________ have forgotten about the meeting — she looked very confused when we mentioned it
"She may - mikght have forgotten about the meeting — she looked very confused when we mentioned it
"They __________ be at the party already; I saw their car outside."
"They must be at the party already; I saw their car outside."
"You __________ use your phone during the exam."
"You MUSTN'T use your phone during the exam."
"He __________ speak five languages fluently — it's very impressive!"
"He CAN speak five languages fluently — it's very impressive!"