Your opinion：These meetings are a waste of time.You say：These meetings；don'；t tend；to be particular；useful.You have used the strategies（）to be more polite.

A.No.1 Avoid negative adjectives by using a negative verb with a positive adjective.

B.No.2 Reduce the strength of what you say， e.g.extremely - rather.

C.No.3 Turn a statement into a question.

D.No.4 Use general and cautious language， e.g.on the whole， in general， tend to， might， etc.

正确答案：No.1 Avoid negative adjectives by using a negative verb with a positive adjective.No.4 Use general and cautious language， e.g.on the whole， in general， tend to， might， etc.