【单选题】聚丙烯酸酯的结构为 ,下列有关它的说法中,不正确的是 [ ]
A.
它可由CH 2 =CH-COOR经加成聚合反应得到
【单选题】由乙烯推测丙烯的结构或性质不正确的是 [ ]
B.
丙烯也能使酸性KMnO 4 溶液和Br 2 的CCl 4 溶液褪色
【单选题】如图所示电路,该电路的反馈类型及反馈极性为( )。【图片】
【简答题】下列数组初始化语句哪些是正确的?( 3 分)A. int[] nums = new int[]{0,1,2,3,4}; B. int[] nums2 = {0,1,2,3,4,5}; C. int[][] num_1 = {new int[]{0,1},new int[]{0,1,2},new int[]{0,1,2,3}}; D. int[][] num_2 = {{0,1},{0,1,2},{...
【多选题】下列数组初始化语句哪些是正确的? ( )
A.int[] nums = new int[]{0,1,2,3,4}
B.int[] nums2 = {0,1,2,3,4,5}
C.int[][] num_1 = {new int[]{0,1},new int[]{0,1,2},new int[]{0,1,2,3} }
D.int[][] num_2 = {{0,1},{0,1,2},{0,1,2,3}}
【单选题】如图所示电路,该电路的反馈类型及反馈极性为( )。【图片】
【简答题】下列数组初始化语句哪些是正确的( )?A. int [] nums = new int[]{0,1,2,3,4};B. int [] nums2 = {0,1,2,3,4,5};C. int [] [] num_1 = {new int[]{0,1},new int[]{0,1,2},new int[]{0,1,2,3}};D. int [] [] num_2 = {{0,1},{0,1,2},...
【简答题】黄曲霉毒素的污染食品有哪些?简述毒性、危害及预防措施。
【单选题】由丙烯生成的加聚物结构是什么?
A.-(-CH(CH 3 ) ─CH 2 -) n -
B.-(-CH(CH 3 ) ─CH(CH 3 )-) n -
C.-(-CH 2 ─CH(CH 3 )-CH 2 -) n -
D.-(-CH 2 ─CH 2 ─CH 2 -) n -