题干
Whenever a patient needs an injection of Penicillin, the doctor does need to make sure whether his patient is ___ to the medicine.
A：sensitive
B：addicted
C：allergic
D：efficient
答案(点此获取答案解析）
C
，如果先用400V电压输送，后又改用2000V电压输送，则输送电压提高后，输电导线上损失的电功率的变化情况是
