look forward to，exchange，organization，challenge，frighten，lecture，
confidence，impress，addict，concentrated on，confuse，has advanced

（1）Our knowledge of the disease

has advanced

has advanced

greatly since 2001.
（2）Going into hospital can be very

frightened

frightened

for a child.
（3）Finding a cure for cancer is one of the biggest

challenges

challenges

facing medical researchers.
（4）The crazy bus schedule has got me completely

confused

confused

.
（5）Some teenagers are

addicted

addicted

to playing video games.
（6）He

concentrated on

concentrated on

reading the book and couldn't hear the noise.
（7）It gives a very bad

impression

impression

if you're late for an interview.
（8）Our school president delivered a（an）

lecture

lecture

on the history of our school on the first day of the new term.
（9）I am

looking forward to

looking forward to

your coming.I have prepared everything for you.
（10）WWF is an international

organization

organization

that works to protect wildlife.
（11）You need patience and

confidence

confidence

to be a good teacher.
（12）Before setting off，I need to

exchange

exchange

the RMB for some American dollars.