请解释最后一句英文的语法But I had never drawn a sheep.So I drew for him
请解释最后一句英文的语法
But I had never drawn a sheep.So I drew for him one of the two pictures I had drawn so often.It was that of the boa constrictor from the outside.
注:the two pictures指the boa constrictor from the inside和the boa constrictor from the outside