阿摩線上測驗
35.We must be ______________guard against our competitor's new market release.
(A) in
(B)on
(C) at
(D)with
答案：登入後查看
統計： A(255), B(457), C(79), D(149), E(0) #652293
統計： A(255), B(457), C(79), D(149), E(0) #652293
詳解 (共 4 筆)
gbhjkl2
#955595
on guard against 警惕
52
1
smiley
#1144050
on guard=on duty值班
20
3
羊駝姊姊（已上電職 感謝阿摩）
#4270471
be on (your) guard
警惕，提防；警戒
6
0
Alina
#937394
???
1
2
