Question: ```
我在饭店里把晚饭吃了吗 =》 My textbook gives me the correct one: 我在饭店里吃晚饭了。

```

My questions are

(1) Why do this sentence not use 把 structure? 

(2) If I rewrite as below, which is grammatically correct? 

* 我在饭店里把三碗米饭吃了。
* 我在饭店里把三碗米饭吃完了。
* 我在饭店里把晚饭吃过三次。(In the restaurant I have had the dinner three times)

Answer: 
Usually when you use 把 you are using passive mode. That was not needed here. You're basically saying "at the restaurant, the rice was consumed by me." It is understandable, but it is also rather awkward. 

I would have to say all three of your alternate versions have the same problem. 

a) I, at the restaurant, 3 bowls of rice were consumed

b) I, at the restaurant, 3 bowls of rice were fully consumed

c) I, at the restaurant, 3 dinners were consumed. 

It would be far more natural to use active vice:

d) 我在飯店裏吃了三碗飯

e) no need to say 吃完了, it is implied

f) I would have said 我去過那家飯店三次了 without specifying dinner. But that's just me.
I think the better answer will be 我在那家饭店吃过三次晚饭。 我在饭店里吃了晚饭。