You must enter the room password. 中文什么意思

you must ____(knock)on the door before you enter you must enter at least one of the followong:wmail You must enter the room password. 中文什么意思 Before you enter the teachers office ,you must (k ) on the door first. you enter the house You must show your r_____ card when you enter the library You must enter a valid 5 digit zip code if you live in the United States. You must enter avalid credit card number You must enter a valid PIN You MUST enter a vaild email address. You must enter a valid birthdate. you must enter a name and a must ask(a,an,无)permission before you enter the room选哪个 Your Message must be between 10 and 160 characters.You must supply a valid country to enter the competition.You must select a country.三句各是什么意思?急! you must enter your real first and last you must enter a valid e-mail address什么意思 You must enter a valid e-mail address 是什么意思 you must be at least tevel 19 to enter