Helpppppppppppppppppp

`1.` Barbara works for a company which make washing machines.

`->` Which thay thế cho vật "it".

`2.` May Day is a day when people don't work.

`->` When thay thế cho thời gian "on that day".

`3.` This is Mrs Jones whose son won the championship last year.

`->` Whose thay thế cho TTSH "her".