( ( If ( ( the Earth ) ( ( did not ) ( have ( an atmosphere ) ) ) ) ) ( , ( then ( ( the Moon ) ( ( would ( disappear completely ) ) . ) ) ) ) )
(ROOT (S (SBAR (IN If) (S (NP (DT the) (NN Earth)) (VP (VBD did) (RB not) (VP (VB have) (NP (DT an) (NN atmosphere)))))) (, ,) (ADVP (RB then)) (NP (DT the) (NNP Moon)) (VP (MD would) (VP (VB disappear) (ADVP (RB completely)))) (. .)))
If the Earth did not have an atmosphere, then the Moon would disappear completely.
(ROOT (S (NP (CD One) (NN way) (SBAR (IN that) (S (NP (DT the) (NN moon)) (VP (VBZ is) (ADJP (JJ different) (PP (IN from) (NP (NN earth)))))))) (VP (VBZ is) (SBAR (IN that) (S (NP (DT the) (NN moon)) (VP (VBZ has) (NP (RB almost) (DT no) (NN atmosphere)))))) (. .)))