情景交际。

1. —Is this_____book?

    —Yes. _____ my book.  And this _____ your pen.

2. —Excuse me. _____  this your ball?

    —_____,  it's not _____ ball. I think it's his ball.

3. —Look! This is my ruler.

   —It_____nice.

4.—_____ this?

   —It's a pencil.

  —_____ do you spell it?

有部分ARPA具有直接询问安全航向的功能，此含义为（）

A、不进行航向试操船而直接向ARPA询问本船应采取的安全航向

B、进行航向试操船后得出的安全航向

C、进行改速试操船后得出的安全航向

D、进行改速试操船前得出的安全航向