1 . Although repetition helps memory, psychologists doubt ________ it helps long-term memory.

A．why

B．how

C．whether

D．what

2 . We listened to the hero, who saved a boy from the fire, ________ his story in detail.

A．having told

B．to tell

C．tell

D．told

3 . Twenty years ago, hardly ________ that they could pay for things with their smartphones.

A．people realized

B．realized people

C．did people realize

D．people did realize

4 . Jim put a table and chair in the spare room ________ his son could have a private place to study.

A．even if

B．only if

C．for fear that

D．in order that

5 . Climate change is an issue ________ has aroused worldwide attention.

A．what

B．which

C．as

D．where

6 . After the experts ________ a whole year on the traffic issue, they finally came to a solution.

A．had spent

B．were spending

C．have spent

D．would spend

7 . Diana got lost. She knew she was ________ in the park, but not exactly where.

A．nowhere

B．somewhere

C．anywhere

D．everywhere

8 . Carol knows a lot about reality shows. She ________ have seen such programs frequently.

A．can

B．would

C．will

D．must

9 . There is some evidence, scientists report, ________ eating garlic may guard against cancer.

A．which

B．that

C．as

D．who

10 . After being stopped by the police, the man admitted ________ the car.

A．stealing

B．steal

C．to steal

D．stolen