Question

I could hardly remember how many times ___ I have failed.

Answer 1

A
这里的times表示次数，所以用关系副词that。我记不清我已经失败多少次了。
关系词的选择依据在从句中所做的成分，先行词在从句中做主、定、宾语时，选择关系代词
(who,
whom,
that,
which,
whose)；
先行词在从句中做状语时，应选择关系副词
(
where
地点状语，when
时间状语，why
原因状语，that则可以用于表示时间、地点、方式、理由的名词后取代when,
where,
why或"介词+
which"来引导定语从句，在口语中that常被省略，例如：His
father
died
the
year
(that
/
when
/
in
which)
he
was
born.
他父亲在他出生那年逝世了。
这句话中，先行词times在从句中作状语，所以关系代词which不能选，剩下ACD项。而由于次数是频率，不属于时间状语，所以不能用when，剩下AD两项。而且，通常在次数前面，一般不加in,
on,
at这一类的介词而直接说
I
have
failed
many
times.所以D项也是不正确的。
所以最终答案选A。并且在口语中，这个that可以被省略。

Answer 2

1。这句话可以是宾语从句。I
have
failed
three
times.
就three
times提问。I
could
hardly
remember
how
many
times
I
have
failed.
这样，就没有正确答案。
2。这道题也可以是定语从句。I
have
failed做times的定语。在I
have
failed
three
times中，three
times做状语，所以可以排除B.which，
次数前不加介词，可以排除D.at
which
，three
times不是时间，可以排除C.when。只有A.that。如果先行词在定语从句中做状语时，可以用that。I
still
remember
the
times
when/that
i
was
young.
Can
you
tell
me
the
reason
why/that
you
were
late?
This
is
the
room
where/that
i
live.