When I asked him _____ the keys, Bob said he had no idea where they were.

wherever

whoever

who

if

was

having been

had been

that he

study

studied

studious

studiously

education

educate

educated

educational

near to

near of

next to

nearly

One of the biggest

The biggest one

Of the biggest one

There are the biggest

Because

Because of

Although

In spite of

Because of

Because

Unless

When

although he isn’t intelligent

because he is intelligent

in spite of his intelligence

despite his intelligent

Not until we arrived at the airport, did we realize that our passports were still at home

We arrived at the airport and realized that our passports are still at home

Not until had we arrived at the airport, we realized our passports were still at home

It was until we arrived at the airport that we realize our passports were still at home