水稻和野慈姑都生活在稻田中，它们因争夺有限资源而发生斗争的种间关系叫____ ；小丑鱼和海葵共居一起、相互依存的种间关系叫____ ．

如图，大楼AB右侧有一障碍物，在障碍物的旁边有一幢小楼DE，在小楼的顶端D处测得障碍物边缘点C的俯角为30°，测得大楼顶端A的仰角为45°（点B，C，E在同一水平直线上），已知AB=80m，DE=10m，求障碍物B，C两点间的距离（结果精确到0.1m）（参考数据： $\sqrt{2}$ ≈1.414， $\sqrt{3}$ ≈1.732）

A：Well，Mr. Jones，we interviewed(面试)three people．Who do you think would be____(good) person for the job?

B：I have to say, I thought Mrs. Shaw was much ____(clever) than the other two，but she wasn't as ____(nice) as the other two．

A：That's true, and we need someone who can work with people．However．I thought Miss Brown would be ____(popular) than Mrs. Shaw and Mrs. Green with our clients (顾客).

B：Yeah．you're right．

A：Thank you for your help．Choosing the proper person is ____(difficult)part of my job．

It's always ____(easy)when I get someone else's opinion．

B：I'm glad I could help．