since much study have not be done previously vs since much study has not been done previously

Some examples from the web:

• There are some things... that should not be done.
• Physical verifications would normally not be done on retained waste.
• According to Commission and Council, amendment 3 would modify the Interinstitutional Agreement, which can not be done by the present technical regulation.
• "It would not be done by concentrating on past achievements rather it would be how we respond to future challenges".
• No, it must not be done.
• First of all, the aforementioned area closures are a good example of how things should not be done.
• If discontinuation during pregnancy is necessary, it should not be done abruptly.
• If discontinuation during pregnancy is necessary, it should not be done abruptly.
• But that should not be done by compulsory textbooks drawn up by the Commission.
• He was sympathetic, but his services and lawyers said it could not be done.
• Driftnets are an example of what should not be done in fisheries policy.
• Let us look first at what must not be done.
• The findings strongly suggested that the funding could not be done via traditional means.
• And it will not be done.
• You may not be done helping people.
• This watered down version of REACH shows how things should not be done.
• I was assured that work would not be done today.
• Determination of fugitive emissions shall be done by a short but comprehensive set of measurements and needs not be done again until the equipment is modified.
• Satisfying wealthy consumers in Europe must not be done at the expense of the food security of developing countries.
• Europe's tariff barriers are, to my mind, an example of how things should not be done.

Some examples from the web:

• My constituent is very concerned that justice has not been done.
• But the ADA has not been done for people like Lucy.
• I accept it has not been done in secret.
• That has not been done in this case.
• This analysis has not been done, therefore all such correlation values might be spurious.
• For the Jasper family justice has not been done.
• There is now a weight of public opinion demanding an answer more sophisticated than: "It has not been done before".
• Since this evaluation has not been done for the Community industry it cannot be said that the Commission is partial in its analysis.
• What you seek has not been done since ages past, and then only in legend.
• We strongly agree that it is necessary to work for the future and to improve on what has not been done well so far.
• Concerning the effect of requiring a weekly instead of a monthly statistical summary this has not been done.
• But I find that the work of the Court of Auditors has not been done sufficiently well to help us to do our job.
• This has not been done, for example, with regard to the effects on employment in Scandinavia etcetera.
• As long as this has not been done, there should be no abolition of duty-free sales.
• That has not been done, but the amendment was indeed tabled.
• We are talking about a minimum declaration, catching up with what has not been done, taking the next step towards greater independence and more comprehensive powers.
• Mr President, it was agreed in committee that something should be added to my original amendment, but unfortunately this has not been done.
• That has not been done; this is why I am expressing a critical judgment.
• This has not been done for a long time and we have now activated that, therefore we will also have good financial control over it.
• Where appropriate, these studies shall include detailed post-mortem macroscopic and microscopic examinations of the injection site if this has not been done under point 1.