Công thức thì hiện tại đơn:

(+) S + am/is/are + V - ing.

(-) S + am/is/are + not + V - ing.

(?) Is/Are + S + V - ing?

Ví dụ: 

(+) I am reading a book.

(-) I'm not reading a book.

(?) Are you reding a book?

-----------------------------------

(+) She is playing the guitar.

(-) She isn't playing the guitar.

(?) Is she playing the guitar?

-----------------------------------

(+) He is listening to music.

(-) He isn't listening to music.

(?) Is he listening to music?

#Học tốt.

Khẳng định : S + am/ is/ are + V-ing

Phủ định : S + am/ is/ are + not + V-ing

Nghi vấn : Am/ Is/ Are + S + V-ing   ?