在下列各句的每个空格内填上一个适当的、完整的单词，该词的首字母已给。
Tom felt too sleepy to keep a______ in history class.
I can’t follow you. Can you e_____________ it to me again?.
Mary is s____________ to be a good learner. Everyone thinks so.
Last month 10 persons were killed in the traffic a_________.
He never does anything at home. He isn’t a h_______ boy. He’s a lazy boy.