When you are introduced to someone, you ________ be sure to stand up before shake hands

Question

When you are introduced to someone, you ________ be sure to stand up before shake hands. A. oughtn’t to B. needn’t  C. must  D. might

VietJack · Accepted Answer

C“must” là động từ khuyết thiếu, mang nghĩa: phải, chắc chắn…

When you are introduced to someone, you ________ be sure to stand up before shake hands.