用所给词的适当形式填空

① It's (know) that the meeting is very successful.

② He said his homework (leave) at home.

③The flowers need (water) every day.

④ —Sam, your schoolbag (must not put) there.

—Sorry, I won't.

⑤Can you come up with (提出)a better way to make the English novel (easy) to read?