油箱可保护变压器铁心和绕组不受外力作用和潮湿的侵蚀,并通过油的对流,把铁心和绕组产生的热量传递给箱壁和散热管,再把热量散发到周围的空气中去。( )
参考答案:对
What he has done is really _____ . Now his parents' are _____ him .[ ]
A. disappointing; disappointed at
B. disappointed; disappointed about
C. disappointed; disappointing by
D. disappointing; disappointed with
下列不属于正式沟通的优点的是
A.效果较好
B.比较灵活
C.有较强的约束性
D.易于保密
E.可以使信息沟通保持权威性