The motorcyclist rounded the corner at a quite unbelievable speed.

=> The speed ............

`->` The speed at which the motorcyclist rounded the corner was quite unbelievable.

Hoặc: The speed which the motorcyclist rounded the corner at was quite unbelievable.

`-` Mệnh đề quan hệ: which, thay thế cho 'the speed'

`-` at` +` (speed): đi với tốc độ

`-` Trans: Tốc độ mà người đi xe máy vòng qua góc cua khá khó tin.

`color{blue}{kashubi}`

`@Answer`

`=>` The speed at which the motorcyclist rounded the corner was quite unbelievable speed

`+` Mệnh đề quan hệ với `Which` : `N` + `Which` + `S` + `V` 

`color{black}{@huyhoang}`

`CHÚC` `CẬU` `HỌC` `TỐT`