根据句意和提示写出单词，完成句子。
（1）We should brush our____ (牙齿) after each meal.
（2）On his mother's____ (四十) birthday, he gave her a card and some flowers.
（3）Does your father like ____ (看) newspapers?
（4）You may____ (借) the book for two weeks.
（5）Now mankind is exploring those ____ (未知的)outer space in many ways.
