it is up to sb to do
问题描述：
it is up to sb to do
答
某人胜任某事
答
由某人做某事
Eg: It's up to you to decide.
由你决定。
It's up to him to do it.
这事该由他做。
答
it is up to sb to do
由某人选择，由某人负责
答
it is up to sb to do
由某人说了算；由某人觉得
It is up to you do decide.
你说了算
答
由谁作主作某事