`1`. It is the first time there has been such an awful disaster like this.
`->` S + have/has + not + Vpp + before = It is the first time + S + have/has + Vpp
`2`. They used to go pass the Masque on Hang Luoc street.
`->` used to + Vinf: đã từng làm việc gì trong quá khứ
`3`. How about taking a trip to the space?
`->` Let's + Vinf = How about + Ving: câu mời, rủ
`4`. An important exam will be taken part in by us next month.
`->` Câu bị động tương lai đơn: S + will be + Vpp