Jenny ____ have kept her word.I wondered why she changed her mind.
If she had known what lay ____ for her, she would never have agreed to go.
The frozen waterfall has attracted floods of tourists to ____ the natural beauty.
Although he has become wealthy, Mr. Wood remains _______ he used to be, modest and friendly.
Modern plastics can _________ very high and very low temperatures.
---What does PM2.5 mean?--- It’s a professional ______ indicating the condition of air pollution.