Task: Question Answering
Input (English): Last night I invited some friends over to my house. It was a nice evening so we decided to build a bonfire. First, we cleared a patch of grass and built a large circle made of big rocks. Next we put some logs around the circle of rocks for us to sit on. Then we went into the woods to gather some dry tree branches and dry leaves. We then put them inside the circle of rocks and made a large pile. We lit a match and put it into the large pile, so the branches and leaves caught fire. It made huge flames, which were nice and hot to sit by. We then sat around the bonfire, told stories, sang songs, and roasted some marshmallows. In a few hours, the fire began to die out, but it allowed us to have a good night. After the bonfire was out, we left and went to bed. 
Question: What kind of wood did they use to build the bonfire?
Output (English): tree branches