______about wild plants that they decided to make a trip to Madagascar for further research.

So curious the couple was

So curious were the couple

How curious the couple were

The couple was such curious

They elected him          captain of the team for         second time.

the; a

a; the

a; a

/; a

考查冠词的用法。句意：他们再次选他当队长。职位，官衔前面不加冠词，a second time表示“又一次，再次”；the second time表示第二次（顺序）。故选D项。

It is six months         the online class started.

that

until

before

since

考查固定句型。句意：在线课程已经开始六个月了。A. that 那，那个；B. until直到..... 为止；C. before在.....之前；D. since自.....以来。分析句子可知，句中涉及固定句型“ It is +一段时间+since引导的时间状语从句”，意为“自从......以来已经有多长时间了”，since从句中用非延续性动词。故选D项。

---Where is Class       ?

---It’s on the       floor.

Six; third

Sixth; third

Six; three

Sixth; three

考查数词辨析。句意：----六班在哪里？---在三楼。英语中表达序号时，如果用基数词表示：名词+基数词，如六班，Class Six;如果用序数词表示：the+序数词+名词，如三楼，即the third floor。故选A项。

The programme can't be             him because it is beyond his ability.

charged with

in charge of

taken charge of

in the charge of

考查固定短语辨析。句意：这个项目不可能由他负责，因为它超出了他的能力。A. charged with控告；B. in charge of负责，主管；C. taken charge of 接管，负责；D. in the charge of 由......负责。根据because it is beyond his ability及空格后him可知用in the charge of 符合题意。故选D项。