Ok

1️⃣ “There is a cat in the room,” said Martha.
👉 Martha said there was a cat in the room.

2️⃣ They started learning the piano five years ago.
👉 They have learned (or have been learning) the piano for five years.

3️⃣ Despite the bad weather, we went to the park.
👉 Although the weather was bad, we went to the park.

4️⃣ “I went shopping yesterday,” said Jenny.
👉 Jenny said she had gone shopping the day before.

5️⃣ “Let’s go out for a walk?”
👉 Shall we go out for a walk?

✨Tổng kết nhanh:

Câu 1 & 4: Câu tường thuật → lùi thì.
Câu 2: Dùng thì hiện tại hoàn thành để diễn tả hành động bắt đầu trong quá khứ, kéo dài tới nay.
Câu 3: “Despite” → chuyển sang “Although” + mệnh đề.
Câu 5: “Let’s …?” → chuyển sang “Shall we …?”