((2R, 5R) - 5 - (6-amino-9h-purin-9-il) - 4-FLUORO-2, 5-dihydrofuran-2-il) oxi) Metro (phenyl) phospholipid) - l-alaninato ethyl ester, pharmaceutical formulation, and therapeutic use in the treatment of viral infection (such as HIV infection). 1. Characteristic 1: a compound selected from this group, which i s composed of the following components: the first ((s) ((2R, 5R) - 5 - (6-amino-9h-purin-9-i L) - 4-FLUORO-2, 5-dihydrofuran-2-il) ox) methyl (phenyl) phosphorus) - l-alanino ethyl ester (the first formula (1))；Form II of ((S) - ((((2R, 5R) -5- (6-amino-9H-purin-9-yl) -4-fluoro-2,5-dihydrofuran-2-yl) oxy) methyl) (phenoxy) phosphoryl) -ethyl L-alaninate (Form II of formula (1))；3. (s) (((2R, 5R) - 5 - (6-amino-9h-purin-9-i L) - 4-FLUORO-2, 5-dihydrofuran-2-il) oxi) methyl (phenyl) phosphorus) - l-alanitroto de ethyl ester (style I (1))；3. (s) (((2R, 5R) - 5 - (6-amino-9h-purin-9-il) - 4-FLUORO-2, 5-dihydrofuran-2-il) oxi) methyl (phenyl) phosphorus) - l-alaninato ethyl ester (style II (1))；Phosphoric acid ((s) - ((2R, 5R) - 5 - (6-amino-9h-purin-9-i L) - 4-FLUORO-2, 5-dihydrofuran-2-il) ox) methyl (phenyl) phosphoric acid (phenyl) phospholipid) - l-alanino ethyl ester (phosphate (1) ester form I)；(s) ((2R, 5R) - 5 - (6-amino-9h-purin-9-i L) - 4-FLUORO-2, 5-dihydrofuran-2-il) oxi) methyl (phenyl) phospholipid) - l-alaninato ethyl ester (xiafonate (1) form I)；and Form I of the acetonitrile solvate of the phosphate of ((S) - ((((2R, 5R) -5- (6-amino-9H-purin-9-yl) -4-fluoro-2,5-dihydrofuran -2-yl) oxy) methyl) (phenoxy) phosphoryl) -L-alaninate of ethyl (Form I of the acetonitrile solvate of the phosphate of formula (1)). Claim 2: A crystalline form of ((S) - (((((2R, 5R) -5- (6-amino-9H-purin-9-yl) -4-fluoro-2,5-dihydrofuran-2-yl ) oxy) methyl) (phenoxy) phosphoryl) -L-ethyl alaninate, herein the crystalline form is Form I of formula (1). Claim 10: A crystalline form of ((S) - (((((2R, 5R) -5- (6-amino-9H-purin-9-yl) -4-fluoro-2,5-dihydrofuran-2-yl ) oxy) methyl)
