超声检查确诊为葡萄胎的特异性声像图表现是
A. 子宫增大,超过妊娠周数
B. 宫腔内充满大小不等无回声区呈“蜂窝状”
C. 子宫肌层回声不均
D. 子宫肌层血运丰富
E. 子宫肌层变薄
葡萄胎分为_________、_________两类
Write a telephone message according to the information below.You are working at an office of a school. It is 11 A.M. A call comes in for Kathy. She is teaching a class. It is Mrs. Ross who wants to sign up for summer classes. She wants Kathy to call her before 3 P.M. today at 426-1103.
预应力混凝土构件的控制截面处于消压状态,则( )
A. 控制截面上任意一点混凝土的应力为零
B. 控制截面的抗裂边缘混凝土的应力为零
C. 控制截面上有拉应力的存在
D. 以上说法都不对