题目

A proposal came up at the meeting _____the protection of giant pandas in Sichuan． A．was concerned with                              B．concerned about C．concerning                                      D．to concern 答案：C小华家额定功率为2000W的电热淋浴器，装满30kg水后连续正常加热35min．水的温度由20℃升高到50℃．已知c水=4.2×103J/（kg•℃），求：（1）加热过程中水吸收的热量；（2）此过程电热淋浴器的热效率．