interact；complicate；cruel；conclude；whisper；concept；remark；compose

（1）It is obvious that the workers haven't learned how to use this

complicated

complicated

machine.
（2）Beethoven is considered to be one of the most famous

composers

composers

in the world，and he created many excellent works.
（3）The author

concludes

concludes

the chapter with a brief summary of her research.
（4）I enjoy the constant

interaction

interaction

with people from other departments in our company，which contributes to better cooperation.
（5）Some students in my class failed to grasp even the simplest mathematical

concepts

concepts

.
（6）Henry

was whispering

was whispering

with his deskmate about a football match when Mr Smith came in.