Consider the difference between discussing two people who started dating 11 months ago, (let's call them Couple I) vs people who started dating 12 months ago (Couple II).

Couple I will have been dating for a year now once another month passes by (this tense is known as Future Perfect).

Couple II has been dating for a year now (this is known as Present Perfect Continuous).

I agree with user 772922, but here is a fuller explanation of the grammar rules.

"Have" and "has" are conjugations of the auxiliary verb used in the present perfect tense. The choice of which one to use has nothing to do with the tense. It is simply dictated by the subject of the verb -- in other words, "who" has or have or had been.

The present perfect tense is used to convey an action that began in the past and continues in the present.

Here is the conjugation of the verb "to be" in the present perfect tense: I have been We have been You have been He/She/It has been They have been

The past perfect tense is used to convey something that happened in the past, a past that occurred before another, later action in the past that you happen to be discussing, as in, "I had made the cookies before we ate."

Here is the conjugation of the verb "to be" in the past perfect tense: I had been We had been You had been He/She/It had been They had been

And that's the rule!

Regarding the original question, it does seem that the subject is not the singular Mrs. Jones, but a plural "they" that includes both Mrs. Jones and a lot of other teachers. So you would use either "have been" or "had been" (but not "has been"). The choice is up to the author, depending on which tense is to be conveyed.

I hope that's helpful.

The site's rules ask for sources. Lots of sources, including the Chicago Manual of Style and a ream of English grammar textbooks I was given throughout my K-12 education, including the once ubiquitous Heath Handbook of English.

It is grammatical, and fully understandable, but few people would say it.

If there was a reason to put it in the passive, I would probably not use the continuous form, but say These have been generated by them in large quantities, adding over a period or over recent months if it was necessary to draw attention to the continuing nature. For most purposes I'd put it actively, and then the continuous if required.

"Had they been" (aware of the danger) is fine, but you need need to change the tense of what comes next. "Had... been" is the past perfect progressive tense, used to indicate a continuous action that was completed at some point in the past. The inversion "had they been" suggests a negative (they had not been aware of the danger). The result of that action needs to be described using a past modal. Past modals are often called called “modals of lost opportunities.” The simple past just tells what happened. Past modals tell what could have, would have, and should have happened.

Had they been aware of the danger, they would have performed regular checks.

Past perfect progressive

Could have should have would have

To begin with, look at your sentence:

"Members of the 16th Lok Sabha worked harder in the budget session than they have in the last 10 years, parliamentary data shows.

I recommend looking at it in two parts:

1. Members of the 16th Lok Sabha worked harder in the budget session
2. than they have in the last 10 years, parliamentary data shows.

Sentence 1 tells you that members of the 16th Lok Sabha worked harder in the budget session. The "budget session" refers to the present budget session, that happened just now, or during the 16th Lok Sabha, if you will.

Sentence 2 introduces a comparison- with how much they have worked in the last 10 years. Now, the idea behind using "have" is to introduce a continuum, a matter of fact that "has been happening" regularly over the past 10 years.

If you use "had" instead, it gives the idea that something HAS happened at a certain point in time, and then that's it. It didn't happen anymore. For instance:

They studied harder this term than they had last year.

Notice how "had" is used to indicate what they did just once, that is last year.

Again, if you now use "have" in the same sentence, see how you get a different meaning:

They studied harder this term than they have in the last five years.

Here, "have" tells you about something that hasn't occurred just once, but has been occurring regularly over a course of time, that is five years.

It's interesting to note that using "had" in part 2 of your original sentence wouldn't make it incorrect, technically. There is a very fine line between using "have" and "had" to denote a continous action in the past tense. As I explained with my previous example, if you use "had" in sentence 2, it indicates that the members of the Lok Sabha had worked up until now, which doesn't fit in well with sentence 1.

And lastly, do take a look at this question on the EL&U site: How do the tenses and aspects in English correspond temporally to one another?. It should give you a clear picture about everything.