Hi Wai Wai,Originally Posted by Wai_Wai
1: In the first example, you would normally use the second, but it depends on the situation. If you mean that she came earlier, and was still in the classroom when they arrived, then use "The teacher was already..."
You would use the second case normally if she HAD BEEN in the classroom, but was no longer there. This is because "had been" refers to something that used to be true, but no longer is.
I'm not sure exactly what you mean in the second example, but if you mean that the teacher was working hard whent he students came in, then you could use either, but probably the second. This is for the exact same reason as last time:
"The teacher was already working very hard when we came in" means that the teacher was working hard when you came in, and continued working.
"The teacher had already been working hard when we came in" means that she had been working hard earlier, but stopped when you came in.
In your final example "Still my mark is a bit worse than the best 5th student," I would start by changing "my mark IS a bit worse..." to "my mark WAS a bit worse...", because you usually refer to a mark being GIVEN to you (ie, in the past), rather than still having a mark.
Next, "the best 5th student" sounds like the best student out of all the fifth students. It doesn't really make any sense.
"The 5th best student" means the fifth student out of all the best students, which is what you mean. "The best students" and "the top students" mean the same thing.
So I'd change your last part of the sentence to: "Still, my mark was a bit worse then the fifth best student."
Hope this helped.