A篇
People faint when the normal blood SUPPLIED
(过去分词做定语,表被动,“供应给脑部的血液”）
to the brain suddenly cut down.This (正确）
can happen if they are SURPRISED by sudden
（surprised“惊讶的”surprising“令人惊讶的”）
news or by something they see.If (去掉it)
（定语从句,原为something that they see,省略了see的宾语that)
a person faints while standing,LAY him
(lie是不及物动词,“说谎；躺；在/位于”；
lay是及物动词,“放；下蛋；铺设”
高考常考考点,必须掌握2词的区别）
down.If his face IS pale,lift his
（与上下文保持时态一致,全文均是现在时）
feet.If he's sitting while he (去掉down）
（sit down,“坐下”,是短暂动作；sit,“坐着”,是状态）
faints,place HIS head between his
（人称一致.这也是高考短文改错题常见考点.）
knees.Untie any tight clothing that might stop him BREATHING castly.Place a
（动词短语：stop sb.(from) doing sth.,“阻止某人做某事”）
cold ,wet cloth on his forehead if POSSIBLE.
（固定短语：if possible,原为：if it is possible,系动词is后应用形容词,不可以用副词possibly）
B篇
1.Different countries HAVE different body languages.For
（主谓一致）
2.example,in Russia,FRANCE and Arab countries PEOPLE kiss （此句有问题,2处错误.kiss前少一主语）
（French,“法国的,法语”；France,“法国”）
3.each other when they MEET,but men in China or Australia shake hands instead of
（时态一致）
4.kissing.People in Pueto Rico like touching,WHILE/BUT
（句意转折）
5.people in Britain do not touch each other.People in Arab countries like (正确)
6.standing close TO one another when they are talking,but
（close to,“靠近”）
7.English people must keep A distance away when they are
（a distance,“一定的距离”）
8.talking.When you use a foreign language,it is very important to know (去掉not)
（句意）
9.the meanings of gestures and MOVEMENTS in the foreign country.
（名词的单复数）
10.FOLLOWING the customs will make your stay there much more PLEASANT and comfortable.(2处错误)
(Following the customs做主语,应用follow的动名词形式；
make + sth.+adj.,使用形容词做make的宾补,不可以用副词pleasantly)
楼主如果真的“马上高考”,那么我建议您有问题应尽量口头问老师,比较节省时间,效果也会更好.