视在功率与有功功率、无功功率组成（）。
A.电压三角形
B.电流三角形
C.功率三角形
D.功率四边形
参考答案：C
简述产褥期产妇的健康指导内容。
The team’s efforts to score were ______ by the opposing goalkeeper.
A. frustrated B. prevented C. discouraged D. accomplished
