典型的心包摩擦音可分为哪几个时相（）
A.心房收缩相
B.心房舒张相
C.心室收缩相
D.心室舒张相
E.心包舒张相
参考答案：A, C, D
We don’t have enough nurses to look after the patients. At least _____ are needed.
A．ten another nurses
B．more ten nurses
C．other ten nurses
D．another ten nurses
斗刃插入力是指装载机铲斗插入料堆的作用力。
