如果x+5=9，y-x=4，y=______．
x+5=9，
x+5-5=9-5，
x=4；
y-4=4，
y-4+4=4+4，
y=8，
故答案为：8．
As a heavy smoker , he finds it hard to get rid of the habit, which has a bad _____on his health.
A．affect
B．effect
C．effort
D．affection
变压器并列运行的条件。
