`1.` As Hanoi has old quarters, pagodas, and a variety of street cuisines, is a huge tourist attraction. 

`-` As: Vì (= Because)`->` As + Nguyên nhân, Kết quả

`2.` Lucy said she wouldn't be here the next day because she was having a party.

`-` Câu tường thuật dạng câu kể:

`->` S + said/said to sb/told sb/... + (that) + S + V lùi thì 

`-` Thì TLD (won't + V-inf) `->` wouldn't + V-inf (lùi thì)

`-` there `->` here 

`-` tomorrow `->` the next day

`-` Thì HTTD `->` Thì QKTD (was/were + V-ing) - lùi thì 

1. As HN has old quarters, pagodas and a variety of street cuisine, it is a huge tourist attraction.

→ Khác với because, khi dùng "as" để giải thích lý do thì lý do đó người nghe/người đọc đã biết rồi.

→ As + S + V + O, S + V + ....

2. Lucy said that she wouldn't be there the day after because she was having a party

- Cấu trúc câu gián tiếp: S + động từ tường thuật (says/said/told…) + (that) + mệnh đề tường thuật

- Lùi thì TLĐ → TL trong QK (would) ; HTTD → QKTD

- tomorrow → the day after