多项选择题
For Questions 16 through 20, select the two answer choices that, when used to complete the sentence, fit the meaning of the sentence as a whole and produce completed sentences that are alike in meaning.
When practicing with a bow and arrow, it is（）to be aware of both the velocity and the trajectory of one’s arrows if one wishes to hit the target.
A. irrelevant
B. necessary
C. conventional
D. prudent
E. detrimental
F. insightful