1

鐳

léi

radium (chemistry)

=2

是

shì

to be (followed by substantives only) correct; right; true (respectful acknowledgement of a command) very well (adverb for emphatic assertion)

=2

是

shì

variant of 是 shì

3

誰

shéi

who also pr. shuí

4

發現

fāxiàn

to notice; to become aware of to discover; to find; to detect a discovery

=5

的

de

of; ~'s (possessive particle) (used after an attribute when it modifies a noun) (used at the end of a declarative sentence for emphasis) (used after a noun, verb or adjective to form a nominal expression, as in 皮革的 pígéde "one made of leather" or 跑堂儿的 pǎotángrde "a waiter (literally, one who runs back and forth in a restaurant)" or 新的 xīnde "new one") also pr. dì or di in poetry and songs

=5

的

dī

a taxi; a cab (abbr. for 的士 dīshì)

=5

的

dí

really and truly

=5

的

dì

(bound form) bull's-eye; target