他上个星期在家里看电视看了二十个小时: Why is 看 written before 电视?
The most straight forward way to form this sentence is a simple SVO structure


[他] [看了] [电视] --&gt; [他] (上个星期在家里) [看了] (二十个小时) [电视]
[S] [V] [O] --&gt; [S] (relative phrase) [V] (relative phrase) [O]
&quot;他看了二十个小时电视&quot; = &quot;he watched 20 hours of TV.&quot;


Another common Chinese sentence structure is [topic + comment] structure


他看电视 is the [topic]
看了二十个小时 is the [comment]
&quot;他看电视看了二十个小时&quot; = &quot;he watches TV., has watched for 20 hours&quot;

(repeat the verb in the comment emphasize the verb)
~
&quot;他电视看了二十个小时&quot; place the object before the verb to emphasize it.