bothers me is that I can't keep my mind on the task, but on personal gains or losses.

What

It

That

One

考查主语从句连接词。句意：困扰我的是我不能专注于任务，而是专注于个人得失。此处为主语从句，从句中缺少主语，结合句意表示“困扰我的是”应用what。故选A项。

---what shall we do tonight then?

---              whatever you want.

Help yourself

No problem

It's a deal

It's up to you

考查交际用语。句意：---我们今晚做什么。---由你决定，你想干什么都行。根据空格后的 whatever you want，以及句意可知空格处填It's up to you由你定。故选D项。

--- I'm afraid I can't complete the marathon next week.

---              ! You have been practicing a lot.

No problem

Go ahead

Cheer up

Good luck

考查交际用语。句意：---恐怕我下周不能完成马拉松比赛。---振作起来！你一直一直在不断练习。A.No problem没问题；B. Go  ahead请干吧；请便吧；C.Cheer up高兴起来；振作起来；D. Good luck祝您好运。由下文可知说话人担心，完不成马拉松比赛，由“你一直不断练习”可推断表示鼓励“振作起来”。故选C项。

All we need          a piece of advice on how we can improve our time management.

are

is

were

was

考查be动词和时态。句意：我们需要的只是一条关于如何改进时间管理的建议。分析句子可知，说明一般情况应该用一般现在时，这句话的主语是All we need, 所以为主语从句，当主语从句作主语时，谓语动词用单数，所以用is。故选B项。

While we may not be born with a nature talent, we can          for it with hard work.

break up

take up

bring up

make up

考查动词短语辨析。句意：虽然我们可能没有与生俱来的天赋，但我们可以通过努力工作来弥补。A. break up打碎；B.take up 拿起，开始从事；C.bring up提出；D. make up 弥补。根据上文we may not be born with a nature talent可知没有与生俱来的天赋，所以要通过努力工作来弥补。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。

What some people regard as a         is seen as a plus by many others.

duty

drawback

failure

faith

考查名词词义辨析。句意：一些人认为是一个缺点，而其他许多人则认为这是一个优点。A.duty责任；B.drawback缺点； C. failure 失败；D. faith信念。根据空后plus“优点”可知，空处需用drawback“缺点”与之对应。故选B项。

Mary never does any reading in the evening, ______.

so does John 

John does too

John does not to

neither does John

主句用never，后面的倒装句相应的用nor或者neither，用完全倒装形式表示后者与前者情况相似。

The wise parents can tell whether their children are telling the truth         they listen to their excuses to wrong deeds.

the first time

every time

for the first time

for every time

考查时间状语从句。句意：每次听孩子对错误行为的辩解，聪明的父母都能分辨出他们是否在说真话。此处引导时间状语从句，表示“每一次” 应用every time。the first time表示“第一次”，与语境不符；for the first time作时间状语，不可引导从句；没有for every time 的表达方式。故选B项。