Theory should by no means be separated from practice. ___, it's important tocombine theory

with practice.[ ]

A. As a result 

B. By the way

C. To be honest  

D. In other words

（）是飞机技术性放行（亦即适航性放行）的责任部门

A.运控中心

B.飞行技术部

C.机务部

D.以上都对