[译] 他养成了吸烟的习惯。
[误] He has formed the hobby of smoking.

[正] He has formed the habit of smoking.
[注] habit 是指个人长期养成，而且一旦养成就很难改掉的“习惯”，它有好有坏，如早起是好习惯，吸烟是坏习惯；hobby 是指个人在业余时间的爱好，没有好坏之说。