与管接头或法兰连接的管子必须是一段直管,这段管子的轴心线应与管接头、法兰的轴心线(),此直线段长度要大于或等于2倍管径。
A.垂直
B.平行
C.相交
D.重合
参考答案:D
Many word processing programs include spell checker. It checks the spelling of every word in a (120) by looking up each word in its dictionary. If the word does not appear in the dictionary the user is (121) to possible misspelling and possible corrections are often (122) . Spell checker does not recognize unusual people names or specialized terms, but it will often allow you to create your own personal dictionary of specialized words you often use. Spell checker is a valuable aid to proofreading, but it can not catch the (123) of one correctly spelled word for another (such as form for from). Thus it does not (124) a document is free of spelling errors.
A.committee
B.correct
C.guarantee
D.prove
溶液中电解质浓度越大,树脂的膨胀性()。树脂在纯水中的膨胀性最大。