We are going to visit the Great Wall this Sunday.-________.

I just don’t understand ______ that leads toso many teenagers becoming addicted to playing computer games.

Huawei is a global leader in telecoms with a great range of smart products to offer, many of __________exported abroad.

What does PM 2.5 mean—It’s a professional ________ indicating the condition of air pollution.

flies ______ a sweet liquid produced by flowers,which bees and other insects collect.