let's______(完整形式)A.let us B.let does
( ) Is the cat ________ the door? No, it isn’t. It’s ________ the desk.
( ) If I ____ you tomorrow, I will give you the receipt. A. see B. will see C. am seeing
( )—— What day is today? —— It's _____ A. Monday B. a fine day C. September 1st
( )The students couldn't help ______ when they heard the joke. A. to laugh B. laugh C. laughing
( ) Do you know ______ this word? A. what to spell B. how to spell C. to spell