`\color{#1c1c1c}{\text{I}}^(\color{#363636}{\text{t}}^(\color{#4f4f4f}{\text{s}}^(\color{#696969}{\text{m}}^(\color{#828282}{\text{e}}^(\color{#9c9c9c}{\text{F}}^(\color{#b5b5b5}{\text{r}}^(\color{#cfcfcf}{\text{e}}^\color{#eee9e9}{\text{d}})))))))`

`=>` Mary doesn't work very hard.

`=>` Từ cần điền vào chỗ trống là: doesn't work

`-----`

Kiến thức:

    `\text{HTĐ}`

`(+)` `\text{S + V/V_s/V_es + ...}`

`(-)` `\text{S + don't/doesn't + V + ...}`

`(?)` `\text{Do/Does + S + V + ...}`