TCP/IP分层模型共有（）层。
A.5
B.3
C.6
D.4
参考答案：D
9. If you plant a tree, you should ____________ the ____________ first.
阅读下面的古诗，回答问题。（4分）
田园乐
王维
桃红复含宿雨，柳绿更带朝烟。
花落家童未扫，莺啼山客犹眠。
小题1:王维的诗“诗中有画”，此诗一、二句描绘了一幅怎样的画面？ (2分)
小题2:此时末句“莺啼”二字在诗中有什么作用？（2分）
My grandpa is 33 years ____________ ____________ my mother.
I ____________ good ____________ yesterday.
The people are ____________ and ____________.
Sometimes I ____________ ____________ after school.
I ____________ ____________ for my friends yesterday.
You can ____________ the No. 3 bus ____________ school.
He likes ____________ ____________.
The rain comes ____________ the ____________.
If you plant a tree, you should ____________ the ____________ first.
Mike often ____________ ____________.