父爱是太阳，即使在乌云密布的日子里，我也能感受到他的光芒。父爱是一棵大树，即使在烈日炎炎的夏日，也会为我撑起一片荫凉。 父爱是一把大伞，即使在风雨交加的路上，也不让一滴水珠落在我身上。父爱是高山，即使在我最困难的时候，也鼓励我永不言弃。父爱是北斗星，即使在伸手不见五指的夜里，也引领我走向成功。请根据提示完成下面这首有关父爱的小诗。

What Is A Dad?

A Dad is like the sun. Even though on cloudy days, I can also feel his light..

A Dad is like the tree . _________小题1:_______, he still holds up a piece of shade for me..

A Dad__小题2:___. Even though on the stormy road, he won’t let a drop of water fall on me.

A Dad is like the mountain. ____小题3:________, he always _______小题4:_________.

A Dad is like the star. Even though in the dark night, he also          小题5:________.

1896年，法国物理学家贝可勒尔发现了（）

A.放射性同位素238轴

B.放射性衰变

C.人工放射性核素

D.放射现象

E.X线