50. Every one (sleep) ………………. at the moment. 

51. I (have) ……………….. these shoes since my eighteenth birthday.

52. I (tidy) ………………….. my desk, but now it’s in a mess again.

53. The last time I (go) …………… to Disney Land was in August. 

54. I’d like to meet a ghost, but I never (see) ……………… any one.

55. Mr. Green (buy) ………………….a new tractor last month.

`color{white}{#MPhuc}`

`50.` is sleeping

`+` at the moment -> HTTD

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

`51.` have had

`+` since -> HTHT

`( + )` S + has / have + V`3`/ed

`52.` tidied

`+` QKĐ : `( + )` S + V`2`/ed + ...

`53.` went

`+` was in August -> QKĐ

`54.` have never seen

`+` never -> HTHT

`55.` bought

`+` last month -> QKĐ

`50`. is sleeping

`51`. have had

`52`. tidied

`53`. went

`54`. have never seen

`55`. bought

`---------------`

`@` Hiện tại tiếp diễn:

`+` S + be + V_ing + O.

`-` S + be not + V_ing + O.

`*` DHNB: at the moment, now,...

`@` Quá khứ đơn:

`+` S + V2/ed + O.

`-` S + didn't + Vnt + O.

`*` DHNB: last + thgian, ago, yesterday,...

`@` Hiện tại hoàn thành:

`+` S + have/has + (never/ever) + V3/ed + O.

`-` S + haven't/hasn't + (never/ever) + V3/ed + O.

`*` DHNB: since + thgian, never, so far,...