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【多选题】
允许所有搜索引擎访问的robots.txt写法正确的是:A.
user-agent:* Disallow:
B.
user-agent:* Allow:/
C.
user-agent:baidu spider Allow:/
D.
user-agent:360Spider Disallow:
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举一反三
【多选题】在氯霉素中间体对硝基-a-乙酰氨基苯乙酮的制备过程中，下列说法准确的是（ ）。
A.
醋酸酐和醋酸钠的加料顺序不同，会引发诸多副反应
B.
加料顺序为先加醋酸酐，后滴加乙酸钠
C.
反应过程中， pH 过高，游离的氨基酮和产物都会发生双分子缩合
D.
加料顺序为先加乙酸钠，后滴加醋酸酐
【单选题】在氯霉素中间体对硝基-a-乙酰氨基苯乙酮的制备过程中，下列说法错误的是（ ）。
A.
加料顺序为先加醋酸酐，后滴加乙酸钠。
B.
反应过程中，pH过高，游离的氨基酮和产物都会发生双分子缩合。
C.
加料顺序为先加乙酸钠，后滴加醋酸酐。
D.
醋酸酐和醋酸钠的加料顺序不同，会引发诸多副反应。
【单选题】We hope this trial transaction will ______ further business between us.
A.
result from
B.
arrange for
C.
comply with
D.
lead to
【简答题】We are writing this letter to tell you that up to now no news has come from you about the goods we ordered on May 25th(上标). As you have been informed in our letters, our customers are in urgent need o...
【简答题】A: Shall we begin to discuss the terms of insurance right now? B: OK. A: We have a deal on CIF price．It means that the insurance should be borne by you, right? B: Certainly．The premium should be paid ...
【简答题】We are writing this letter to tell you that up to now no news has come from you about the goods we ordered on May 25th. As you have been informed in our letters, our customers are in urgent need of th...
【简答题】简要回答木架建筑存在哪些缺陷
【单选题】We hope this initial transaction will ___ further business between us.
A.
result from
B.
arrange for
C.
comply with
D.
lead to
【单选题】听力原文：Man: The thing is, he was a very good customer of ours until about five years ago, when we had that safety problem with the R21. He didn't reply to our literature or anything for all that time, a...
A.
a health and safety official
B.
an estate agent
C.
an insurance broker
D.
a journalist
E.
a foreign buyer
F.
a lawyer
G.
a marketing consultant
H.
a travel agent
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