those young men were so excited___seeing ththose young men were so excited___seeing the famous singer.a.on b.at c.by d.at
问题描述：
those young men were so excited___seeing th
those young men were so excited___seeing the famous singer.
a.on b.at c.by d.at
答
D at表原因,再如Moreover,Heifer China is the first NGO providing aid here,so all people here were so excited at our arrival.小母牛中国办是第一个援助这里的非*组织,所以村民看到我们都很高兴....