diff --git a/oblong.c b/oblong.c
index c0543c2..5975c5c 100644
--- a/oblong.c
+++ b/oblong.c
@@ -680,26 +680,26 @@ void get_fasta_dims ( int * mync , int * mynt )
     char c ; 
     int curnt = 0 , curnc = 0 , atnc ; 
     char * nampt = strsp ;
-    while ( !feof ( inp ) && i != '>' ) i = getc ( inp ) ;
-    if ( i != '>' ) {
+    while ( !feof ( inp ) && i != '>' ) i = getc ( inp ) ; //没读到 EOF 并且不是 > 继续，直到读到 >
+    if ( i != '>' ) { //读到最后没有 > 报错
       fprintf ( stderr , "\nError reading fasta file --expected taxon name\n" ) ;
       errout ( 1 , NULL ) ; }
-    while ( !feof ( inp ) ) {
-        fscanf ( inp , " %s" , nampt ) ;
+    while ( !feof ( inp ) ) { //没读到 EOF 不停
+        fscanf ( inp , " %s" , nampt ) ; //从 inp 读到 nampt
         i = 0 ;
         ++ curnt ; 
-        if ( curnt == 1) 
+        if ( curnt == 1) //第一次
             while ( 1 ) {
                 fscanf ( inp , " %c" , &c ) ;
-                if ( c == '>' || feof ( inp ) ) break ;
-                ++ curnc ; }
-        else {
+                if ( c == '>' || feof ( inp ) ) break ; //读到 > 或者 EOF
+                ++ curnc ; } // 读到 > 或者 EOF curnc ++
+        else { //第二次及之后
             atnc = 0 ; 
             while ( 1 ) {
                 fscanf ( inp , " %c" , &c ) ;
                 if ( c == '>' || feof ( inp ) ) break ;
                 ++ atnc ; }
-            if ( atnc != curnc ) {
+            if ( atnc != curnc ) { //到最后比较
                 fprintf ( stderr , "\nError reading fasta file --it seems not to be aligned\n" ) ;
                 errout ( 1 , NULL ) ; }}}
     * mync = curnc ;
@@ -715,22 +715,22 @@ void read_multifiles ( void )
     int atfile = 0 , numfiles = 0 ; 
     char ** taxnam ; 
     double prop , secs , prevprop ;
-    clock_t beg , end ;
-    beg = clock () ;
+    clock_t beg , end ; // 定义起始时间
+    beg = clock () ; //计算时间
     errout ( ( tmpp = fopen ( "oblong.tmp" , "wb" ) ) == NULL , "Cannot open temporary file, \"oblong.tmp\"" ) ; 
     // Find out total NT and total NC
     multinp = inp ; 
-    maskinit ( ) ; 
-    taxnam = ( char ** ) myalloc ( MAXMULTITAXA * sizeof ( char * ) ) ;
-    fscanf ( inp , " %s" , nampt ) ;
-    while ( !feof ( multinp ) ) {
-        ++ numfiles ; 
-        if ( ( inp = fopen ( nampt , "rb" ) ) == NULL ) {
+    maskinit ( ) ; //maskinit 函数
+    taxnam = ( char ** ) myalloc ( MAXMULTITAXA * sizeof ( char * ) ) ; //default MAXMULTITAXA 1000 L32
+    fscanf ( inp , " %s" , nampt ) ; //FILE * inp = NULL 读入文件到 nampt
+    while ( !feof ( multinp ) ) { //feof 如果 EOF 返回非 0，没有EOF 返回 0，
+        ++ numfiles ; //numfiles 初始为 0
+        if ( ( inp = fopen ( nampt , "rb" ) ) == NULL ) { // r readbale b binary 二进制可以防止 Windows下文件问题
             fprintf ( stderr , "\nCannot open file %s (from list of multiple files)\n" , nampt ) ;
             exit ( 0 ) ; }
-        if ( reporttoscreen ) 
+        if ( reporttoscreen ) // L60: default 1 L309:0 
            fprintf ( stderr , "%cChecking input file %3i %-40s" , reportheader , numfiles , nampt ) ; 
-        if ( fasta ) get_fasta_dims ( &nc , &nt ) ;
+        if ( fasta ) get_fasta_dims ( &nc , &nt ) ; //get nc and nt
         else {
            i = fscanf ( inp , " %i %i" , &nt , &nc ) ;
            if ( i < 2 ) {
@@ -750,7 +750,7 @@ void read_multifiles ( void )
                   if ( !strcmp ( nampt , taxnam[ i ]  ) ) matched = i ; 
             if ( matched < 0 ) {
                 errout( curnt >= MAXMULTITAXA , "Sorry, cannot deal with so many distinct taxon names (change MAXMULTITAXA and recompile)" ) ;  
-                taxnam [ curnt ] = ( char * ) myalloc ( MAXNAMELEN * sizeof ( char ) ) ;
+                taxnam [ curnt ] = ( char * ) myalloc ( MAXNAMELEN * sizeof ( char ) ) ; //MAXNAMELEN = 1000 default
                 strcpy ( taxnam [ curnt ++ ] , nampt ) ; }
             if ( fasta ) -- nampt ; 
             for ( b = 0 ; b < nc ; ++ b ) {