旋转钻井系统由那些部分组成？

YZ-1型制动机双阀口式中继阀排风口不严或列车管系及折角塞门泄漏，当操纵大闸手把到保压位，会造成均衡风缸保压，列车管压力（）。

治疗病毒性心肌炎时下列不是选用糖皮质激素的适应证的是（）

A.难治性心力衰竭

B.房室传导阻滞

C.心源性休克

D.存在自身免疫

E.窦性心动过速

高温高压井结构设计应考虑中间技术套管必须封固目的层以上各种低压、坍塌、漏失、压力过渡带等井段，保证套管鞋以下地层能承受（）。

A、重量

B、高压

C、低压

D、温度

甜豌豆的紫花对白花是一对相对性状，由非同源染色体上的两对基因共同控制，只有当同时存在两个显性基因时，花中的紫色素才能合成。下列说法中正确的是（）

A.一种性状只能由一种基因控制

B.基因在控制生物体的性状上是互不干扰的

C.每种性状都是由两个基因控制的

D.基因之间存在着相互作用

UML-based tools are often used for J2EE/.NET application analysis and design, both because UML’s object orientation is ideal for the J2EE/.NET implementation (66) and because of the expanding scope and complexity of today’s enterprise endeavors. (67) the approaches diverge at the coding/implementation phase, a common set of analysis and design techniques applies to both J2EE and.NET.
The use of a virtual machine (VM) architecture is also common to J2EE and .NET. Application development tools (68) intermediate-level code instead of platform-specific binary code, which means the VM interprets that code in real time or performs Just-In-Time (JIT) compilation; the Microsoft VM always runs JIT-compiled code. This VM-based model results in (69) -independent applications and is conducive to the late-binding technique that’s (70) to the OO approach.

A．Although

B．However

C．But

D．Thus