问题补充：
I don’t want to express any opinions on the plan until it has been .
A. tried out
B. watched out
C. come out
D. let out
答案：
(答案→)A. tried out
B. watched out
C. come out
D. let out
解析：本题考查动词短语辨析。句意：对此计划,在验证之前我不想表达任何观点。try out试验；
watch out当心；come out出现； let out放出。
