银河系是星系的典型代表，由（）多亿颗恒星和星际物质组成。
参考答案：
1500
—Lucy,do you prepare for your trip?
—No, I don’t. I will ____ the best way to have our trip.
A．decide on
B．decide
C．decide to
D．decide in
实验室最适温度和湿度？
