A student will probably attend four or five courses during each ________.

He asked me ___________ Zhang Hua came to school or not. 

— What would you like to have, meat or fish?

— _____________________.

— I would like to make an appointment for the meeting. Which day would you prefer, Tuesday or Thursday?

— _________________ 

It's ___________ to point to or talk about strangers in public.

— ___________________

— Once or twice a week.

— Which city has _________population, Beijing, Guiyang or Nanchang?

— Beijing, of course.

分别标出如图所示1_______________2_______________3_____________4___________5___________部位。

如下图所示，在第①组的胚芽鞘套上不透光的锡纸小帽，在第②、③、④组胚芽鞘的各部位插入云母片（不允许生长素穿过），沿箭头方向给予单侧光照射。
（1）请根据上述条件分别说明①。④组胚芽鞘的生长情况。

①________________________________；
②________________________________；
③________________________________；
④________________________________。
（2）以上实验说明，感受光刺激的部位在______，向光弯曲生长的部位在______。

如图脐带血管有3条，A是______，B是______。血管周围胶样结缔组织如图中C称为______。
 

分别标出如图所示1_______________2_______________3_____________4___________为哪根血管。