题目

1. The soldier did what they could_________(save) the people under the ruins(废墟）after the    earthquake . 2. What great fun we had_________________(dance) at the party last night! 3. It’s said that 32 people ____________(die) from H7N9 so far. 4. She couldn’t work out the problem, so he asked her teacher for help___________(wise). 5. ________(prevent) the communicable diseases, the doctors did as much as they could. 6. Look, this beautiful stamp must be one of those__________(direct). 7.My deskmate is often heard__________(sing) after class. 8..The_______of Xi Jinpin made 如图所示，直角梯形ACDE与等腰直角△ABC所在平面互相垂直，F为BC的中点，∠BAC=∠ACD=90°，AE∥CD，DC=AC=2AE=2．（Ⅰ）求证：平面BCD⊥平面ABC（Ⅱ）求证：AF∥平面BDE；（Ⅲ）求四面体B-CDE的体积．