After AlphaGo defeated human Go champion, we started to worry about whether AI(人工智能)_________the place of human some day in the future.

Trees can stop the sand _____ towards the rich farmland in the south.

Orange represents ________. It can cheeryou up when you are feeling sad.

Mom, can I go out and play with my friends now?—No, honey, you can’t _____ you haven’t recovered from the knee injury

Why_______ to ask your friends to have dinner in Sunshine Restaurant