题干
— What did your father do yesterday?
— He ________ at home and read a book.
A：stay
B：stayed
C：is staying
D：stays
答案(点此获取答案解析）
B
— What did your father do yesterday?
— He ________ at home and read a book.
A：stay
B：stayed
C：is staying
D：stays
时，可以确保山体不滑坡．某小学紧挨一座山坡，如图所示，已知
，斜坡
长30米，坡角
．改造后斜坡
与地面成
至少是多少米？（精确到0.1米）