I always watch TV ___half an hour every evening.填介词

I always watch TV ___half an hour every evening.填介词
I always watch TV ___half an hour every evening.填介词

I always watch TV ___half an hour every evening.填介词
for
我没玩看半小时电视
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填for
我总是每晚看半个小时电视。

for+一段时间