简述房屋拆迁的原则。
参考答案：
（1）符合城市规划。（2）有利于城市旧区改造。（3）有利于生态环境改善。（4）保护文物古迹。
Researchers at Children’s Hospital of Pittsburgh announced they had discovered ______ evidence that a virus is involved in what used to be called juvenile diabetes.
A. incessant B. compelling C. identical D. problematic
工序质量的高低反应在（）。
