Question

--have you ever been to beijing before?--No.it it the first timethat I ____here.

1--have you ever been to beijing before?--No.it it the first timethat I ____here.A.amB.beC.have beenD,had been 2The rever used to be very clearn,but now it smells bad for it ______seriously.ApollutesBwas pollutedChas pollutedDhas been pollutedлл~~~

Answer 1

C解释it is the first time that sb后面用现在完成时，如果is变成was则要用过去完成时hadD解释现在完成时表示已经发生的事情，河是被污染的所以用被动

Answer 2

1. C因为前面有the first time，所以后面用现在完成时
2. D 因为说以前很干净，现在应该是受污染，应该是从以前一直到现在都受污染。

Answer 3

答案CD 采纳个哦

Answer 4

C；D