将盛有适量水的容器放在水平地面上，用弹簧测力计将系有细线的铁块浸没在水中处于静止状态，此时弹簧测力计的示数为F，如图所示.

(1)若细线突然断了，铁块沉到容器底部静止，此时地面受到的压力和原来相比▲(选填“不变”、“变小”或“变大”).

(2)已知月球对物体的引力是地球对同一个物体引力的1/6，若在月球上做此实验，将容器放在月面上，实验情况仍如图所示，当铁块处于静止时，弹簧测力计的示数▲(选填“等于零”、“等于F/3”或“等于F/6”).

He refused to tell us whether he ________ (undertake) the job.

努力工作 (译成英语 )_________

Those who’d like to visit the exhibition ________ (sign) your names here.

Da Ming comes from China，he is _____(China).

he( 物主代词 )__________

I think the ______ (four) lesson is the most difficult in this book.

We were busy ________ (get) things ready for the trial production when he phoned us.

Night ________ (fall), we hurried home.

如图，∠ B=∠ D=90°， BC=DC，∠ 1=40°，则∠2=______度.