高一英语问题---人教必修一1、I wonder if it's because I haven't been able

高一英语问题---人教必修一
1、I wonder if it's because I haven't been able to be outdoors for so long that I've grown so crazy about everything to do with nature.
问：wonder在这里是什么意思?grow
2、I can well remember that there was a time when a blue sky,the song of the birds,moonlight and flowers could never have kept me spellbound.
问：前半句中,well修饰的是remember,well在这里是什么意思?there was a time是不可数名词,为什么前面有一个a?when在这里是什么意思,起什么作用?后半句中,为什么用现在完成时“have kept”?keep sb.do sth.既然是do,为何用现在分词spellbound?
3、It's no pleasure looking through these any longer because nature is one thing that really must be experienced.
问：“It's no pleasure looking”是什么意思?look through是什么意思?really前面要不要加一个主语it?