组成植物种子的主要结构是
①种皮②胚芽③胚轴④胚根⑤子叶⑥胚乳 [ ]
A.①②③④
B.③④⑤⑥
C.②③④⑤
D.①②⑤⑥
答案:C
先观察,找出规律后再填空.
21×9=189
321×9=2889
4321×9=38889.
54321×9=______
987654321×9=______.
Nowadays ________ Internet is becoming increasingly popular and new high speed broadband network was recently started.
A.a; the
B.the; a
C.a; a
D.the; the