`1`. Her classmates weren't invited to the party.

`-` Bị động QKĐ: S + was/were + V-pII + (by O)

`2`. The woman asked her husband if Martin and Lisa had just got engaged.

`-` Câu tường thuật: S + asked/wondered/wanted to know + if/whether + S + V(lùi thì)

`-` HTHT `->` QKHT

`3`. If we allow people to hunt endangered species, they will become extinct sooner.

`-` Câu điều kiện loại `1`: If + S + V(-s/es), S + will/modal verbs + V-inf

`4`. I haven't called her since she left me.

`-` S + have/has + not + V-pII + since + V-ed/c2

`5`. Happiness and health is the most precious.

`-` So sánh hơn nhất: S + be + the + adj-est/most adj

`6`. Even though it rained, a lot of people came to the concert.

`-` Even though + S + V, S + V: Mặc dù

1. Her classmates weren't invited to the party.

-> Bị động

2. The woman asked her husband if Martin and Lisa had just got engaged?

-> Câu tường thuật

3. If we don't allow people to hunt endangered species, they will become extinct sooner.

-> Câu điều kiện loại I

4. I haven't called her since she left me.

-> thì HTHT

5. Happiness and health is the most precious.

-> So sánh nhất

6. Even though it was rain, a lot of people came to the concert

-> In spite of - Even though