What does the sign say?

----- Nội dung dịch tự động từ ảnh -----
17. What does the sign say?
NOTICE
STUDENTS MUST
TURN OFF CELLULAR PHONES
BEFORE ENTERING
SCHOOL BUILDING
18. What does the sign say?
Leie Language Center
TURH of
Beginner
Advchend
Set and Sun
Men & Wed (6.30-8.00)
Tues & Thurs (5.00-6.30)
Mon & Fri (6.30-8.00)
OFF
A. Students must leave their mobile phones at home.
B. Students must not show their mobile phones to their friends.
C. Students must turn off their mobile phones after getting into campus.
D. Students must switch off their mobile phones before getting into campus.
A. There are no classes on Saturdays and Sundays.
B. There are classes of three levels every day.
C. There are advanced classes only on Fridays.
D. Times for classes are the same.