A: 1
B: 2
C: 3
D: 4
举一反三
- Among the following conclusions, the correct one is ____________.[img=415x210]1802e8730f6b36b.jpg[/img] A: The system is unstable. B: Link 2 is a redundant restraint. C: O is an instantaneous joint. D: O is not an instantaneous joint. E: The system is stable with no redundant restraints. F: The system is stable with 1 redundant restraints. G: The system is instantaneously unstable.
- which is the transfer function model for the system in the diagram?[img=577x523]17de64be134fb10.jpg[/img] A: 1 B: 2 C: 3 D: 4
- In the following mechanism, it has redundant constraints.[img=185x179]1803a1af94d1dec.png[/img] A: 0 B: 1 C: 2 D: 3
- 下列碳正离子稳定性顺序应是( )。(1)[img=55x29]17e0abbe7d0cf4b.png[/img] (2)[img=124x28]17e0abbe86207a6.png[/img] (3)[img=51x28]17e0abbe8f27381.png[/img] (4)[img=61x28]17e0abbe989993f.png[/img] A: (3)>;(4)>;(1)>;(2) B: (4)>;(3)>;(1)>;(2) C: (3)>;(4)>;(2)>;(1) D: (1)>;(4)>;(3)>;(2)
- Viewing: Number these events from 1-4 in the order they happened.[img=477x327]1803de18453944c.png[/img] A: 1 B: 2 C: 3 D: 4
内容
- 0
下列化合物发生消去反应活性顺序是( )。(1)[img=68x22]17da6fc510f381b.png[/img] (2)[img=69x22]17da6fc521ce86c.png[/img] (3)[img=80x18]17da6fc53238d27.png[/img] (4)[img=97x18]17da6fc54228f3d.png[/img] A: (2) ＞ (1) ＞ (4) ＞ (3) B: (2) ＞ (1) ＞ (3) ＞ (4) C: (1) ＞ (2) ＞ (3) ＞ (4) D: (1) ＞ (2) ＞ (4) ＞ (3)
- 1
设随机变量X服从指数分布E(1)，则[img=160x49]1803b3b76d193f4.png[/img]= A: 4/3 B: 1 C: 2/3 D: 2
- 2
设随机变量[img=75x25]1802d5ab02ff46a.png[/img]，且已知 E[(X - 1)(X + 2)] = 6，则[img=30x19]1802d5ab0aa816f.png[/img] A: 1 B: 2 C: 3 D: 4
- 3
下列化合物与NaCN发生反应(SN2)的速度快慢次序( )。(1) [img=79x64]17da6fd5a1d97eb.png[/img] (2) [img=262x38]17da6fd5b576813.png[/img] (3)[img=36x18]17da6fd5ccbc7d3.png[/img] (4)[img=87x59]17da6fd5ed269d9.png[/img] A: (2)＞(3)＞(1)＞(4) B: (1)＞(4)＞(2)＞(3) C: (2)＞(4)＞(1)＞(3) D: (1)＞(2)＞(3)＞(4)
- 4
下列化合物与NaCN发生反应(SN2)的速度快慢次序( )。(1)[img=79x64]17e0a99ef923fa1.png[/img](2)[img=171x25]17e0a99f044e7db.png[/img](3)[img=48x24]17e0a99f0e1e99a.png[/img](4)[img=87x59]17e0a99f1762202.png[/img] A: (1)>;(2)>;(3)>;(4) B: (1)>;(4)>;(2)>;(3) C: (2)>;(3)>;(1)>;(4) D: (2)>;(4)>;(1)>;(3)