连词 and / but 连接句子 — 英语选择题
题目
Nina is kind. She helps her classmates. She is tired. She helps her friend, too. 选择合适的连词依次填入两组句子：Nina is kind, ___ she helps her classmates. She is tired, ___ she helps her friend. A. but；and B. and；but C. and；and D. but；but