Linda,make sure the tables____ before the guests arrive.A.be

Linda,make sure the tables____ before the guests arrive.A.be set B.set C.are set D.are setting
如果有E答案 will be set
2010年吉林市二模题：
-How about buying sam a mobile phone?after all ,he isn't a boy any more.
-I think it necessary,for we sometimes want to make sure if he _home for dinner.
A.will come B.comes C.has come D.would come
这两个题类似吗?请指教,