    Sentence 2: Since:. NASA’ didn't .kriow: how:  Many attempts: each’ test ‘would: erid up  requiring. what: did. they’ use. instead: of  numtbers ‘for the trials?, ’* .    Séntence ‘2: In September "1967, : Mueller  approved a sequence. of: ‘mission types:  which‘ had’ to’ be: successfully.-accomplished  “in, order. to. achieve: the: manned lunar  landing, 2