1.　Eric: It will be nice and sunny this weekend. David: Good idea! Let’s go 　( 31 )　 in the mountains in Yangmingshan(陽明山). 　Eric: That’s a good idea. But 　( 32 )　 can we get there? David: We have to 　( 33 )　 the MRT to Shihlin(士林) or Shipai(石牌) . And then we can go there by bus. After that,  we can 　( 34 )　 in the mountains. There are also many special insects and plants 　( 35 )　the way.　
Eric: Oh, I see!
(31)
(A) 　bird watching　　
(B) watch birds　
(C)　watches the bird　
(D)　to bird watch