which they need vs which they needed

Both phrases are correct, but they are used in different contexts. 'Which they need' is used in present tense to refer to something that is currently required, while 'which they needed' is used in past tense to refer to something that was required in the past.

Last updated: March 22, 2024 • 3973 views

which they need

This phrase is correct and commonly used in English.

This phrase is used in the present tense to refer to something that is currently required by someone.

Examples:

They can choose which books they need for their research.
The store provides a variety of tools which they need for their projects.

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If we are anything less than ambitious in this field, we shall simply not provide our industry, our research and development experts with the modern patent which they need.
Shipping companies have acquired more entrepreneurial room, which they need in order to secure a good return on investments.
They have already achieved a great deal but there remain difficult tasks to tackle, for which they need our common support.
whereas, although meeting the full range of demographic challenges is principally the task of the Member States, the regions must be proactive, for which they need European-level support,
The Commission has, however, made one very important proposal that would be a great help to small and medium enterprises: it is substantially to raise the threshold above which they need to declare turnover tax in advance, i.e. register for VAT.
New rules are now in force, under which users of Wi-Fi have to pay for a connection, for which they need to provide an e-mail address to have a password and a username sent.
It will ensure a legally secure, predictable, effective and sustainable solution for those countries which want to use the system to get the affordable medicines which they need.
The only way to achieve a sustainable increase in the employment rate is to give companies the entrepreneurial room for manoeuvre which they need in the form of framework conditions.
F. whereas, although meeting the full range of demographic challenges is principally the task of the Member States, the regions must be proactive, for which they need European-level support,
Print larger denominations, for which they need a metal press plate.
We give them a huge influx of capital, which they need.
The Arab countries are facing a series of challenges which they need to tackle by means of substantial improvements in the political, economic and social fields.
The Council considers it a priority to support the work of the three level 3 committees, for which they need suitable supervisory tools.
The Commission has identified benchmarks for both countries, which they need to fulfil in these critical areas.
It must also be complete and naturally offer consumers the information which they need to be able to make the necessary investment.
The role of crisis management institutions must be clarified to ensure that operators receive this information which they need for making decisions.
Drivers often face unforeseen hold-ups, as a result of which they need to have more frequent breaks to eat, for example.
Third, the proposal increases the legal certainty for operators and traders, which they need to carry out their daily business.
That's because train companies put seats in their carriages, which they needn't do with this.
To this end, the Member States should assess the resources which they need to make available to the contact points so that they can fully carry out their duties.

Alternatives:

which they require
which they want
which they desire
which they must have
which they seek

which they needed

This phrase is correct and commonly used in English.

This phrase is used in the past tense to refer to something that was required by someone in the past.