王芳4分钟打字240个，照这样计算，她20分钟能够打字多少个？
240÷4×20
=60×20，
=1200（个）．
答：她20分钟能够打字1200个这字．
That is the best way you thought of _______ into trouble.
A．stopping some young people to get
B．to prevent some young people getting
C．keeping some young people getting
D．preventing some young people getting
氧化风机启动允许条件有哪些？
