When it comes to modern communication, network safety is always a major          . 

concern

advantage

opportunity

solution

考查名词辨析。句意：当涉及现代通信，网络安全一直是一个主要令人担忧的问题。A. concern关心，令人担忧的事实或情况；B. advantage 优势；C. opportunity 机会；D.solution解决方案。网络安全一直是现代通信的个主要令人担忧的问题。故选A项。

Daniel has undertaken to keep the secret, so he won’t tell anyone even though ______.

asked to keep

to be asked

to ask

asked to

考查省略和过去分词。句意：丹尼尔答应保守这个秘密，所以即使问他也不会告诉任何人。此处是even though引导的让步状语从句，从句主语和主句主语都是he，和ask之间是被动关系，相同的主语和be动词可以省略，所以这里是过去分词作状语，且ask sb. to do sth.可以省略与前面相同的部分，只留下动词不定式符号to。故选D。

---My mother hardly watches any sports shows.

---_____.

So do mine

So does mine

Neither do mine

Neither does mine

“so＋助动词（情态动词或连系动词）＋另一主语”，此句型是主谓倒装结构，可以表示前面的情况也适用于后者，使用该句型需要注意以几个方面的问题： 1．该句型只能用于肯定句，不能用于否定句：如果前句是否定句，则要用“neither ／nor ＋助动词＋主语”。 2．句型中的主语与上文中的主语是不同的两个主语3．句型中助动词，包括连系动词和情态动词的时态要和上句中谓语动词的时态相一致。根据上文,我母亲几乎从来不看体育节目.——我的（母亲）也是。结合语境可知下文指的是另一个人的母亲，故用名词性物主代词做主语，上文hardly表示否定含义，故下文用否定形式，选D。

Tom wanted to play football with his friends in the street，but his father told him ________.

not to

not to do

not do it

do not to

考查动词不定式的省略。完整的形式应该是…，but his father told him not to play football with his friends in the street.为避免重复，常省去不定式动词，保留不定式符号to，故选A。

Though it is a          job, he  still devotes much time and energy to it.

poor-paying

poorly-paying

poorly-paid

poor-paid

考查构词法。本题中考查了复合形容词的构词法，“使用副词+过去分词” 构成新的形容词，如“newly-discovered”最新发现的；本句中“poorly-paid报酬极少的”。句意：尽管这是一份报酬极少的工作，但他仍然花了很多时间和精力做它。故选C项。

It has been warned that        to the surroundings with people infected by Covid-19 without any

protection can lead to severe result.

being exposed

exposed

having exposed

to expose

考查非谓语动词。句意：有人警告称，在没有任何保护措施的情况下，暴露在有感染 Covid-19的人环境中会导致严重的结果。分析句子结构可知expose在句中应用非谓语动词形式，表示“暴露”短语为be exposed to,且从句中缺少主语，expose 与主语people是被动关系，故应用动名词的被动式作主语。故选A项。

If you want to catch the first bus you'd better         for the bus station immediately.

set up

set about

set down

set off

考查动词短语辨析。句意：如果你想赶上第一班公交车，你最好马上动身去车站。A. set up建立；B. set about开始做.....;C. set down 记下；D. set off 出发，动身。结合上文If you want to catch the first bus you'd better可知此处指“动身，出发”，应用set off。故选D项。

So difficult __________ it to work out the problem that I decided to ask Tom for advice.

 I did find 

did I find

 I have found  

have I found

句子使用的基本句式为so…that…结构。按英语语法，当该结构的so…置于句首时，其后的句子(主句)要用倒装语序，如：So loudly did he speak that even people in the next room could hear him. 他讲话声音那么大，隔壁屋里的人都听得见。

Like other animals, we are          until we know it is safe to relax.

on purpose

on fire

on guard

on duty

考查介词短语辨析。句意：像其他动物一样，我们在知道安全的时候才放松警惕。A.on purpose 故意；B. on fire着火；C.on guard 警惕；D.on duty值班。结合后文we know it is safe to relax，可知我们在知道安全的时候才放松警惕。故选C项。

You don't have to know the name of the author to find a book. You           find the book by the title.

must

need

can

would

考查情态动词辨析。句意：你不需要知道作者的名字就能找到一本书。你可以按书名找到这本书。A.must必须，一定；B.need 需要；C. can可能；可能；D.would愿意。根据句意可知，此处表示一种客观的可能性，应使用情态动词can。故选C项。

The small car can't         a large family inside.

suit

press

collect

fit

考查动词词义辨析。句意：这辆小汽车装不下一大家子人。A.suit 相配，合身；B.press压；C.collect 收集；D. fit合适；容纳。suit表示尺寸和大小方面适合；此处表示小汽车容纳不下一大家子人。故选D项。

Only when he returned ________ that the war had ended and the army had come back.

we tell

we told

did we tell

were we told

考查倒装句型。Only放在句首时，句子要用倒装语序；根据句意“我们被告知”可知，此处要用were we told。故答案选D。