1. Work hard and you will pass the exam. (用if改写)
    ______ you ______ work hard, you ______ ______ this exam.
2. I don't know where I should visit. (同义句)
    I don't know                                                    .
3. She could speak English at the age of five. (同义句)
    She ______ ______ ______ ______ English at the age of five.
4. The baby panda weighs about 100g. (对划线部分提问)
    ______ ______ ______ the baby panda ______?
5. Skiing is interesting. Diving is interesting, too. (合并为一句)
    Skiing                                                 diving.