1. (+) My mother is cleaning the kitchen now

    (- ) My mother isn't cleaning the kitchen now

    (? ) Is your mother cleaning the kitchen now?

2. (+) He worked in Hanoi in 2010 

    (- ) He didn't work in Hanoi in 2010

    (? ) Did he work in Hanoi in 2010?

3. (+) I will return to my hometown in 2 years

    (- ) I won't return to my hometown in 2 years

    (? ) Will you return to your hometown in 2 years?

*Cấu trúc thì hiện tại tiếp diễn:

(+) S + is/ am/ are + V_ing

(- ) S + is/ am/ are + not + V_ing

(? ) Is/ Am/ Are + S + V_ing?

*Cấu trúc thì quá khứ đơn:

(+) S + V_ed/ V2

(- ) S + didn't+ V_inf

(? ) Did + S + V_inf?

*Cấu trúc thì tương lai đơn: 

(+) S + will + V_inf

(- ) S + won't + V_inf

(? ) Will + S + V_inf?

$1.$ $...$

$(+)$ My mother is cleaning the kitchen now.

$(-)$ My mother isn't cleaning the kitchen now.

$(?)$ Is your mother cleaning the kitchen now?

*S + tobe + V-ing.

$2.$ $...$

$(+)$ He worked in Hanoi in 2010.

$(-)$ He didn't work in Hanoi in 2010.

$(?)$ Did he work in Hanoi in 2010?

*S + V (-ed/ bất quy tắc).

$3.$ $...$

$(+)$ I will return to my hometown in 2 years.

$(-)$ I will not return to my hometown in 2 years.

$(?)$ Will you return to your hometown in 2 years?

*S + will + V (Bare).