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【单选题】
粗盐中含 Ca 2+ 、 Mg 2+ 、 Fe 3+ 、 SO 4 2— 及泥沙等杂质,需要提纯后综合利用。粗盐提纯的步骤有: 1 加入过量的 Na 2 CO 3 溶液; 2 加入过量的 BaCl 2 溶液; 3 加入过量的 NaOH 溶液; 4 加盐酸调节溶液的 pH ; 5 溶解; 6 过滤; 7 蒸发。正确的操作顺序是 ( )A.
⑤①③②④⑥⑦
B.
⑤①②③⑥④⑦
C.
⑤③①②⑥④⑦
D.
⑤③②①⑥④⑦
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【单选题】听力原文：M: Mary，who's the guy you were with at the movie theatre last night? W: Oh，he's Mark. He's my English teacher. He's learning Chinese from me and the film was my lesson for him. Q: What do we lear...
A.
Mary's English teacher is Mark．
B.
Mary's Chinese teacher is Mark．
C.
Mary and Mark are good friends．
D.
Mary and Mark are office colleagues．
【单选题】听力原文：W：Were you caught in the rain last night? M：No，I was already safe inside the house． Q：What happened last night? (18)
A.
It rained for a short while.
B.
There was a' car accident.
C.
There was a fire.
D.
It snowed heavily.
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