有4袋糖，其中一袋少装了几块要用天平把它找出来，至少称（ ）次，才能找出来。
2
After Mary and Caroline covered 25 kilometers that day, their legs________.[ ]
A. gave in
B. gave off
C. gave out
D. gave away
辐射供冷的冷却顶板，在实际设计中其供水温度多采用（）。
A．7℃
B．12℃
C．16℃
D．20℃
