3. 二元一次方程的正整数解有( )个。
A. 1 B. 2 C. 3 D. 4
2. 若是二元一次方程，则( )
A. B. C. D.
1. 下列方程组中，是二元一次方程组的是( )
25. now that 既然；由于 Now that we have no money, we can’t buy a new car.
just now ① right away 刚刚 ② now 现在 from now on 从现在开始
a number of 大量的 the number of …的数目
权所有：()
版权所有：()
24. take no notice of = pay no attention to 不加以注意 without notice 不事先通知
notice sb do 注意…做完了… notice sb doing 注意…正在做…
23. have nothing to do with 与…无关 to say nothing of 何况；更不必说
22. take note 记笔记 a note of thanks 感谢信
21. Not at all. 别客气。 not only ... but also 不仅…而且…
not ...but... 不是…而是 not that ... but that ... 不是(因为)…而是(因为)…
20. talk nonsense 胡说 talk business 谈正经事
make nonsense of 搅乱 The depression made nonsense of our plan.
19. None of the students is/are ... none but 只有 They choose none but the best.他们只挑最好。 none other than 不是别人正是… He is none other than our headmaster.
的正整数解有( )个。
是二元一次方程，则( )
B. 
C. 
D. 
B. 
C. 
D. 