复数$z=1+2i$，$\stackrel{-}{z}$是z的共轭复数，则$\frac{\stackrel{-}{z}}{z}$对应的点在（    ）

放电影时，电影胶片上的图案经凸透镜在银幕上成的是（  ）

1）y=|cos（2x+ $\frac{\pi }{6}$ ）|最小正周期为π；

2）函数y=tan $\frac{x}{2}$ 的图象的对称中心是（kπ，0），k∈Z；

3）f（x）=tanx﹣sinx在（﹣ $\frac{\pi }{2}$ ， $\frac{\pi }{2}$ ）上有3个零点；

4）若 $\overrightarrow{a}$ ∥ $\overrightarrow{b}$ ， $\overrightarrow{b}\parallel \overrightarrow{c}$ ，则 $\overrightarrow{a}\parallel \overrightarrow{c}$

其中错误的是____

    When you are in England, you must be very careful in the street because the traffic drives on the left. Before you cross a street, you must look to the right first and then the left. If the traffic lights are red, the traffic must stop. ____ If the traffic lights are green, ____ The people on foot must not cross. In the morning and in the evening when people go to or come back from work, the streets are very busy.

____ Always remember the traffic moves on the left. So you must be careful. ____ In many English cities, there are big buses with two floors. You can sit on the second floor. From there you can see the city well. ____

A. the traffic can go.

B. There is no need for you to look around.

C. Have a look first or you will go the wrong way.

D. When you go by bus in England, you have to be careful, too.

E. It is very interesting.

F. The people on foot can cross the road carefully.

G. It is really strange.

— __________. That man got his books and left a few minutes ago.