1 . Although________ as the most dangerous road in our country, China's National Highway 318, is known as the "heavenly road" for its amazing views.

A．regarding

B．to regard

C．regarded

D．regard

2 . 如果可能的话，我暑假想去北京。
__________ __________, I will pay a visit to Beijing.

3 . If        in a scientific way, this kind of dog will be able to work as a guide for the blind.

A．training

B．having trained

C．trained

D．to train

4 . 让我惊讶的是，我儿子的作业比预期完成得要好。
To my surprise, my son finished his homework ________________．

5 . 只要有可能，他们就让他停下并问他这三个问题。
________________, they would stop him and ask him the three questions.

6 . 他们的友谊一旦失去，就无法再挽回。
________________, their friendship won’t be won back.

7 . ________ ________, we suggest that you lie down and rest.
如果可能的话，我们建议你躺下休息。

8 . 尽管是战前制造的，这台发动机仍然处于良好状态。
________________, the engine is still in perfect order.