根据句意及汉语提示完成单词
问题描述：
根据句意及汉语提示完成单词
1.I have been to Shanghai ____（两次）.
2.The robot can ____（探测）dangerous places.
3.He is my best friend.He can keep ____（秘密）for me.
4.I keep a ____（日记）every day to help me remember things.
5.The old man lives ____（孤单的）.
答
1.twice
2.explore
3.secret
4.diary
5.alone