Question

紧急 请大家帮助我 几道英语选择题

下面有几道英语选择题希望大家能尽量帮助我解答，我正在准备明年续本科，现在晚上在学校上提高班，可是老师讲题的水平实在不敢恭维，只能靠自己自学，所以好多题自己很难弄懂，所以大家帮帮我 谢谢啦
注明：希望每道题大家能解答出为什么选这个 不选其它的？
1. The last half of the nineteenth century_______the steady improvement in the means of travel
A has witnessed B was witnessed C witnessed D is witnessed
正确答案A .请问为什么不可以选择B？或者其它呢？
2. It was very kind of you to do the washing-up ,but you___it.
A mustn’t have done B wouldn’t have done Cmightn’t have done Ddidn’t have to do
正确答案D。请详细解释一其余
3. Why hasn’t she come back yet?
She ___your invitation
A should have forgotten Bcan’t have forgotten Cought to have forgotten D may have forgotten
正确答案D 请详细解答一下其它为什么不选
4. Be careful! They____the door
A painted B was painting Chave painted Dhave been painting
正确答案D 为什么？
5. We ___the matter but no decision ___about it.
Ahave been considering , has been made Bhave been considering ,was made
Chave been considering ,is made D have considered ,were made
正确答案A 为什么？
6Hand in your papers when you ___ the test
A are finishing Bwill finish Chave finished Dwill have finish
正确答案C。请问为什么不是D或者其它呢？
6. We can go only when the ground ___
A is drying B has dried Cdried D will dry
正确答案B 为什么不是其它呢？
7. In case he ___,let me know
A will come Bwould come Ccomes D come
正确答案C
8. Smith is to study medic as soon as he ___military sevice
A will finish B has finished Cfinsh Dwould finish
正确答案B
9. Once you __that brand of whisky ,you will never want to drink any other
Adrink B have drunk Cwill drink Ddrank
正确答案B
10.Did you write to Grance last summer?
No but I’ll ___her over Christmas vacation
A be seen B be seeing Chave seen D have been seeing
正确答案B
11.The construction of the lab ___before the end of next month
Amust have completed Bmust have been completed
Cmust be completed Dmust complete
正确答案B
12 The information is urgently __
Aneed Bneeding Cnecessary Dneeded
正确答案D

Answer 1

read the grammar book you will understand all; it's all about perfect progressive tense.

Answer 2

I've answered your question..