Ⅰ.单句语法填空
1．He felt ____________(embarrass) as soon as he realized that he had asked a foolish question.
2．She ought to ____________ (attend) your birthday party, but she had to look after her mother in hospital.
3．________ is no need to push him to concentrate on studies.
4．In ________(conclude), people around the world should protect the water resource.
