Choose the word ( A, B, C or D ) that best fits the blank space in the following passage

Choose the word ( A ,B,C or D ) that best fits the blank space in the following passage :                                             Life an astronaut can (19) ... really difficult . They have a checklist (20) ... every day . Because (21) ... no gravity, they also have to exercise for two hours a day to keep healthy . Thay need to wear (22) ... whenever they go outside . Astronaut don't use real beds . Thay (23)... use sleeping bags and lock their sleeping bags to the wall . Thay also need to use wet toweld to wash because water ( 24)... around the space station .                  19. A.be     B.have      C.do        D.bring                                                                                                                  20.A.completing        B.to complete      C.to take      D.talking                                                                                21.A.It's     B.There are     C.There has     D.There's                                                                                              22.A.a spacesuit     B.a space station     C.a space clothes     D.a spaceship                                                        23.A.have     B.are     C.need to     D.don't                                                                                                              24.A.appears     B.moves     C.runs     D.floats