题目内容：
The earned value technique is a commonly used method of performance measurement. It integrates project scope， cost， and schedule measures to help the project management team assess project performance. If a project’s Schedule Performance Index（SPI=EV/PV） value less than 1.0， it means that （ ）.
A.the project is ahead of its planned schedule
B.less work was completed than was planned
C.the cost overrun for work completed
D.the cost under-run of performance to date
参考答案：【答案仅供学习，请勿对照自行用药等】
答案解析：