“5.7”空难发生后，“黑匣子”的打捞工作始终是人们关注的焦点，为了尽快将它打捞出水，专家们在失事海域进行探测，测量船在海面向海底发射波速为1450 m/s的超声波，并测得超声波从发射到反射回海面经历的时间为0.2 s,则“黑匣子”所在的海域的深度约为多少？

（1）Could you give me some____ ? I want to make a call. (零钱)

（2）This pair of shoes is too expensive. Would you please show me____ pair? (另一)

（3）Bring your____ and show them to your classmates.(录像带)

（4）Are more and more people ____ in shopping online? (感兴趣的)

（5）I met an old friend of my____ in the street yesterday.(祖父母)

（6）The shopping list ____  some food and drinks. (include)

（7）____ the Chinese New Year is very exciting. (celebrate)

（8）He____  made this beautiful ring for his wife. (special)

（9）My family will hold a party for my father's ____ birthday. (forty)

（10）The Smiths are____ to go to Hainan on holiday this winter. (plan)

如图所示，正方体ABCD﹣A₁B₁C₁D₁的棱长为8cm，M，N，P分别是AB，A₁D₁，BB₁的中点．

（1）画出过M，N，P三点的平面与平面A₁B₁C₁D₁的交线以及与平面BB₁C₁C的交线；

（2）设过M，N，P三点的平面与B₁C₁交于Q，求PQ的长．