Paul is good, kind, hard-working and intelligent; ________, I can’t speak too highly of him．

as a result

in a word

by the way

on the contrary

To improve their oral English, everyone in the class is supposed to ________ actively in these discussions．

participate

attend

enter

take

Stronger and more lasting memories are likely to be formed ________ a person is relaxed．

where

unless

when

although

Nearly four hundred supermarkets in Beijing are preparing to dim(使暗淡)their lights ________ the "Earth Hour 2010" on Saturday night．

honor

honoring

to honor

having honored

A salty diet may increase the risk of stomach cancer ________ 10 percent, South Korean researchers found in a study of more than 2 million people．

at

to

by

for

The first textbooks ________ for teaching English as a foreign language came out in the 16th　century．

to be written

written

being written

having written

Some people are worrying about the possibility ________ mobile phones could be responsible for a range of illnesses, from rashes(皮疹)to brain tumors．

that

why

how

whether

It is the ________ in Britain that young people often do not shake hands when they meet someone for the first time．

custom

habit

hobby

favour

Rose found her toy bear ________ under the chair．

hiding

to hide

having hidden

hidden

As we joined the big crowd, I got ________ from my friends．

lost

separated

spared

missed