单选题
下列4条直线：l1：2x－3y＋5＝0；l2：3x－2y＋1＝0；l3：3xsinα－2ysinα＋7＝0．l4：
．其中与直线2x＋3y－10＝0垂直的是（ ）.
A
l1，l2
B
l2，l3
C
l1，l2，l4
D
l3，l4
单选题
_____ our great surprise, our company has made much more profit than we expected last year.
A
For
B
In
C
With
D
To
单选题
You can ask these experts _____ advice in job hunting.
A
on
B
over
C
from
D
for
单选题
When I first arrived in Japan, I was surprised _____ the way people greeted each other.
A
of
B
to
C
with
D
at
单选题
方程ax＋by＋c＝0与方程2ax＋2by＋c＋1＝0表示两条平行直线的充要条件是（ ）．
A
ab＞0，且c≠1
B
ab＜0，且c≠1
C
a2＋b2≠0，且c≠1
D
a＝b＝c＝2
单选题
若O为坐标原点，过点P（rcosα，rsinα）（r≠0），且垂直于OP的直线方程为（ ）．
A
ycosα＋xsinα＋r＝0
B
ysinα＋xcosα＋r＝0
C
ysinα－xcosα－r＝0
D
ysinα＋xcosα－r＝0
