根据句意和汉语注释，写出单词的正确形式。
XiJinping, our ____________arrived in Seattle beginning a state visit of the USA on 22^nd
September, 2015.  (国家主席)
Jim with his classmates often ____________ Maths problems after class.  (讨论)
The English book must be Lily’s because her name is on the ____________. (封面)
______________, he caught the early bus to school this morning. So he wasn’t late.  (幸运)