8. The visitors a________ the beauty of the natural park so much that they visited it a second time.

7. I was pleased that he gladly a_________ our invitation.

6. He told me about his a___________ on the lonely island.

5. “Would you please place the piano with its back a________ the wall? In case you might damage it.”

4. There are strong a___________ for and against capital punishment.

3. I made an a_____________ to my host and left early.

2. He caused his parents great a__________ by cycling long distance alone.

1. The a_____________ of the royal birth was broadcast to the nation.

17．給定兩個(gè)長(zhǎng)度為1的平面向量和，它們的夾角為。如圖所示，點(diǎn)C在以O(shè)為圓心的圓弧上變動(dòng).若其中,則的最大值是=________.

瑞安中學(xué)2008學(xué)年第二學(xué)期高二年級(jí)期末考試

16．由“若直角三角形兩直角邊長(zhǎng)分別為a、b，則其外接圓半徑r =” 類(lèi)比可得“若三棱錐三條側(cè)棱兩兩垂直， 側(cè)棱長(zhǎng)分別為a、b、c，則其外接球半徑r =