题目

Directions: For each blank in the following passage there are four words or phrases marked A, B, C and D. Fill in each blank with the word or phrase that best fits the context.As the coronavirus pandemic shuts down public life on the streets, a new kind of life is opening up online. Many people who are1enough to still have their jobs are working from home, often experimenting with video chats and virtual offices for the first time. The outbreak could change the internet as2 as it is changing our hand washing habits.Our range of 3 apps has already started to shift. Almost overnight, the video c洁净的空气对于人类和其他动植物都是非常重要的，但随着工业发展，空气遭到污染，空气污染的来源有哪些，如何保护空气 （各写一条即可）．