1. 为什么呆在家里?

[ wèi shén me dāi zài jiā lǐ ? ]

Why did you stay at home?

2. 为什么不让我去接你呢?

[ wèi shén me bù ràng wǒ qù jiē nǐ ne ? ]

Why don't I pick you up at your house?

3. 你为什么不去参加一个有氧健身班呢?

[ nǐ wèi shén me bù qù cān jiā yī gè yǒu yǎng jiàn shēn bān ne ? ]

Why don't you attend an aerobic class?