1.
Infinitive attributive vs. of+-ing attributive;
不定式定语与of+-ing式定语
2.
A tramp steamer.
不定航线的不定期货船
3.
(grammar)either of the determiners `a/an'(the indefinite article)or `the'(the definite article)
冠词（不定冠词a/an或定冠词the)
4.
indefinite pronoun
ph.1. 【语】不定代词
5.
infinitive particle
(动词)不定式助词
6.
To go is an infinitive.
“to go”是动词不定式。
7.
It's not at all certain whether I'll come tomorrow.
我明天还不定来不来呢。
8.
not settled or established.
不固定的，不确定的。
9.
To be undecided or skeptical.
不确定不能肯定或怀疑
10.
the quality of being unstable and insecure.
不稳定，不可靠，不安全。
11.
I don't konw for sure, it depends.
我不能肯定，视情形而定。
12.
"Have you decided? No, I haven't decided yet."
你决定了吗？ 不，还没決定。
13.
These arrangements tend to be unstable.
这些协定都是不稳定的。
14.
B: I` m not sure, but I think he` s up to no good.
我不太确定，不过我想他一定不怀好意。
15.
A victory is unlikely but not impossible.
胜利不一定有希望但也不一定不可能。
16.
"He can't have got the fire to light ....
“一定是火烧不燃。… …
17.
unsound cement
变质[不安定]水泥
18.
"I'm perfectly certain Ah Ying won't be coming here tonight;
“阿英一定不来了！