When you travel to foreign countries，you'll realize how important itis to learn English．（改写句子，句意不变）
You'll realize the of learning English when you travel ．
David played basketball on the playground just now．（对划线部分提问）
basketball on the playground just now？
Lisa does the housework every day．（改为否定句）
Lisa the housework every day．
Didn't he see you just now？（根据句意做出肯定或否定回答）
，he ． He said hello to me．
China is the greatest country in the world．（改为同义句）
China is greater than country in the world．
People will have robots at home in 20 years．（对划线部分提间）
will people have robots at home？