A government official was murdered last Friday and the police are collecting information that is ____ to the case.

Air is________and of no smell but we can feel its motion when there is a wind. 

--- What’s the model plane look like? --- Well, the wings of the plane are ______ of its body.

It is reported that 70% of people in China are ________ about the food security situation after  so many accidents.

 At least 30 percent of the government speeches abandon ______ tones and embraced the most popular cyber words developed by Chinese netizens in the past year, for example, fuyun (floating cloud, indicating vanity).