Help the exhausted college student leave a polite but firm note for their extremely messy roommate. Select ALL the grammatically correct sentences that express a strong obligation.
The correct answers are You must wash... and You have to wash...
Both must and have to are used to express strong obligation in the present tense.
"Must" is a modal verb and is never followed by "to" (so "must to" is incorrect).
"Have to" changes to "has to" only for third-person singular subjects (he/she/it), so "you has to" is incorrect.