4. The country mouse/mice has got a small house. 5. We have got two foot/feet. 6. She has got one child/children.

4. The country mouse has got a small house. (Мышь, а не мыши, так как дом один.) 5. We have got two feet. (У нас две ноги, множественное число feet, а не foot.) 6. She has got one child. (У неё один ребёнок, единственное число child, а не children.)