______ label to each of the trees, with detailed introduction of their features, and visitors will know more about them and how to protect them.
| A．To attach | B．Attach |
| C．Attached | D．Having attached |
With online course Crazy English has over 20 million students all over China __________ the class through the Internet .
| A．attend | B．attended | C．attending | D．to be attending |
He sat back on the chair, took a book and began to read, ___.
| A．being looked at ease | B．looked rather at ease | C．to look rather at ease | D．looking rather at ease |
At the computer operation test, one is supposed to stay at his own machine, keep his eyes on his screen, ______ to anyone.
| A．and not to speak | B．but could not speak | C．instead of speaking | D．or rather speak |
______ as the “First Lady of Speech”, Dr Lillian Glass is recognized as one of the world’s leading experts on communication skills.
| A．Knowing | B．Having known | C．Known | D．To be known |
It rained nonstop for ten days , completely _____ our holiday.
| A．to ruin | B．ruined | C．having ruined | D．ruining |