给加横线的字注音
决定____ 艰巨____ 竣工____
- Lucy, what were you doing at nine last night?
- I ___________ the piano. I usually practice the piano at that time.
①必须加强国际合作②意识形态不同的国家难以合作③互不侵犯,和平共处④和平来之不易,悲剧不能重演
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