I couldn't be present myself, but I sent my ________ to the meeting．

agent

represent

representative

representation

Tom likes playing football and Mary is ________ playing table tennis．

keen on

keen in

fond on

fond to

Taobao.com is a free site, ________ visitors can not just buy almost all kinds of products but open their own online shops．

whose

which

what

where

________ the employee's working efficiency, the supervisor will allow them to have a coffee break．

Improving

To improve

Having improved

Improved

You should try not to get ________ in the trouble between them．

lost

absorbed

trapped

involved

When talking about China, people often ________ it with the Yellow River．

associate

worship

line

relate

To my astonishment, everyone present took on a ________ look hearing the ________ news．

surprised; expected

surprising; expected

surprised; expecting

surprising; expecting

When you have finished the book, please ________ it on the shelf．

replace

take place

take place of

in place of

Bill was doing a lot of physical exercise to build up his ________．

ability

force

strength

energy

He stepped into the office, ________ down and began to work at once．

sitting

to sit

having sat

sat