- Các động từ khuyết thiếu đã học là :
+) must : You must do the homework now
+) may : I may go to the moon in the future
+) can : I can go there in 5 minutes
+) should : You should do morning exercise regularly
+) could : I could swim 5 years ago
+) shall : We shall go shopping tomorrow
+) would : He looks so tired . He would get up late tomorrow