采煤工作面上隅角瓦斯浓度（）时，必须停止工作。 A.超过1％ B.达到1.5％ 发布时间：2019-01-15 05:29 │ 来源：www.tikuol.com 题型：单项选择题 问题： 采煤工作面上隅角瓦斯浓度（）时，必须停止工作。A.超过1％ B.达到1.5％ C.超过1.5％ D.达到3％
题型：单项选择题 "Culture shock" occurs as a result of total immersion in new culture. It (51) to "people who have been suddenly transplanted abroad. " Newcomers may be anxious (52) they do not speak the language, know the (53) , or understand people’s behavior in daily life. The visitor finds that "yes" may not always mean "yes", that friendliness does not (54) mean friendship or that statements that appear to be serious are really intended (55) jokes. The foreigner may be unsure as to when to shake hands or embrace, when to (56) conversations, or how to approach a stranger. The (57) of "culture shock" helps explain feelings of bewilderment and disorientation. Language problems do not account for all the frustrations that people feel. When one is (58) of everything that was once familiar, such as understanding a transportation system, knowing how to register for university classes, (59) knowing how to make friends, difficulties in coping with the new society may (60) .A．arouseB．riseC．ariseD．raise 查看答案
题型：单项选择题 测定铵盐中氮含量时，一般先用浓硫酸分解试样，再加NaOH使NH3蒸馏出来，然后通过硼酸吸收，最后用标准的盐酸滴定，化学计量点的pH值应在（）范围内。A、弱碱性B、弱酸性C、强碱性D、强酸性 查看答案