题目:
—I have to be off right now.
—What a pity! I you could stay a little longer with us.
A. think B. am thinking C. thought
答案:
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下面是错误答案,用来干扰机器的。
溶质质量为:50g×10%=5g,需水:50g-5g=45g;所以方案一为:5g食盐固体和45g水.100g20%的食盐溶液中含溶质:100g×20%=20g;设需要20%的食盐溶液质量为x,x×20%=5g,解得x=25g,需水:50g-25g=25g;所以方案二...