A．单句填空
1．—Where is Peter? I can't find him anywhere.
—He went to the library after breakfast and________ (write) his essay there ever since.
答案 has been writing [句意：——彼特在哪？我哪也找不到他。——早饭后他去了图书馆，从那以后他一直在那写论文。根据句中的时间状语ever since可知，write 这一动作从过去某一时刻一直持续到现在，故用现在完成进行时has been writing。]
2．At college, Barack Obama didn't know that he________(become) the first black president of the United States of America.
答案 was to become [句意：在上大学时，巴拉克·奥巴马不知道他将成为美国第一位黑人总统。根据句意可知，“上大学”发生在过去，从过去的时间看将来，要用过去将来时，故用was to become。]
3．The reports went missing in 2017 and nobody ________(see) them since.
答案 has seen [句意：这些报告在2017年就丢失了，此后再也没人见到过它们。由题干中的since可知，本题应用现在完成时。]
4．—Hi, let's go skating.
—Sorry, I'm busy right now. I ________(fill) in an application form for a new job.
答案 am filling [句意：——嗨！让我们去滑冰吧！——很抱歉，我现在很忙。我正在填申请新工作的表。此处表示正在进行的动作，故用现在进行时。]
5．She ________(phone) someone, so I nodded to her and went away.
答案 was phoning [句意：她当时正在给别人打电话，因此我朝她点了一下头就走开了。根据句意可知，此处表示“当时她正在打电话”，所以用过去进行时。]
6．—Sunny Taxi Service. Can I help you ?
—My plane________(take) off at 11：30 in the morning. Can you send a taxi no later than 9 o'clock?
答案 takes [句意：——阳光出租车服务。我能帮您吗？——我要乘坐的航班上午11：30起飞，你能在9点前派一辆出租车吗？介绍飞机、火车等公共交通工具的时刻表常用一般现在时。]
7．Jack doesn't smoke now, but he ________(smoke) for almost twenty years.
答案 smoked [句意：杰克现在不抽烟了，但他(曾经)抽了近20年。题干中有延续性的时间状语for almost twenty years，表示的是与现在无关的过去动作，应该用一般过去时。]
8．I________(drink) a cup of coffee when a new idea occurred to me.
答案 was drinking [句意：我正在喝咖啡时突然想出来一个好主意。从occurred可知主句表示过去的动作正在进行，故用过去进行时。]
9．I'm afraid I can't recognize Ann when we meet, for I ________(see) her for 30 years.
答案 have not seen [句意：恐怕当我们相见时我都认不出Ann了，因为我30年没见她了。此处指从过去到现在已经30年了，故用现在完成时。]
10．In order to make up the missing notes, he ________(try) his best to spend as much spare time as possible doing this job these days.
答案 has been trying [句意：为了补丢失的笔记，他这些天一直在努力用尽可能多的业余时间做这项工作。根据句意及these days可知，此处强调从过去某个时间开始到现在一直在做的事情，因此用现在完成进行时。]
B．单句改错
1．In the last few years, China made great achievements in environmental protection.
________________________________________________________
答案 made前加has [根据时间状语in the last few years用现在完成时。]
2．—Dr Jackson is not in his office at the moment.
—All right. I call him later.
________________________________________________________
答案 call前加will [表示“临时决定”。]
3．—Is Peter coming?
—No, he had changed his mind after a phone call at the last minute.
________________________________________________________
答案 去掉had [根据语境可知，改变主意发生在过去某一时间，故用一般过去时。]
4．—What time is it?
—I have no idea. But just a minute, I check it for you.
________________________________________________________
答案 check前加will [表示接下来要发生的动作。]
5．The twins, who finished their homework, were allowed to play badminton on the playground.
________________________________________________________
答案 finished前加had [“完成家庭作业”发生在“被允许打羽毛球之前”是“过去的过去”，故用过去完成时。]
6．The Russian rocket designer has died. For many years, he had served as a deputy to the father of the Soviet space program.
________________________________________________________
答案 去掉had [由语境可知，当助手应该为过去的事，故用一般过去时。]
7．—Have you got the sleeping bag needed for the camping this weekend?
—Yes, I have bought it almost the moment I heard the news.
________________________________________________________
答案 去掉have [此处应与heard保持一致，故用过去时。]
8．—Do you still remember the name of the company?
—I'm really sorry. The name escaped from my mind.
________________________________________________________
答案 escaped前加has [根据语境可知，此处指过去的动作对现在的影响，故用现在完成时。]
9．—How is your grandma recently?
—She feels quite good after the operation, but her health has taken a turn for the worse.
________________________________________________________
答案 feels→felt [此处说的是过去的事情，故用一般过去时。]
10．—Can I help you, madam?
—No, thank you. I wait for my order.
________________________________________________________
答案 wait→am waiting [根据上下文语境可知答话者正在等待，故用现在进行时。]