—Could you tell me the________ of making such tasty cakes?
—Well, I just follow the directions in the cookbook.
A:feature
B:plan
C:cost
D:trick
在相同时刻的物高与影长成比例,如果高为1.5米的测竿的影长为2.5米,那么影长为30米的旗杆的高是( )