interrogative pronoun "kiu", is "kiel", how, in what way, to what
degree:

Kiel oni vivas en tia aero? How do people live in such air?
Kiel afabla sxi estas! How amiable she is!
Mi miras kiel la batalo okazis, I wonder how the battle happened.
Kiel longe li pensis pri gxi? How long did he think about it?

THE PLUPERFECT TENSE.

135. The compound tense formed by combining the past active participle
with the past tense of "esti" represents an act or condition as having
been completed at some time in the past, and is called the "pluperfect
tense". The conjugation of "vidi" in this tense is as follows:

mi estis vidinta, I had seen (I was having-seen).
vi estis vidinta, you had seen (you were having-seen).
li (sxi, gxi) estis vidinta, he (she, it) had seen (was having-seen).
ni estis vidintaj, we had seen (we were having-seen).
vi estis vidintaj, you had seen (you were having-seen).
ili estis vidintaj, they had seen (they were having-seen).


CARDINAL NUMERALS.

136. Cardinals are numeral adjectives which answer the question "How
many?" The cardinals from one to twelve are as follows:

unu = one. sep = seven.
du = two. ok = eight.