The phrase "are needed to knock" is correct and usable in written English.
It can be used when discussing the requirements or tools necessary for knocking, whether literally or metaphorically.
Example: "In order to gain entry, certain permissions are needed to knock on the door of opportunity."
Alternatives: "are required to knock" or "are essential to knock".
In her autobiography, Littlewood made no bones about the fact that a lot of work was needed to knock Delaney's play into shape.
But if you have a mind to put it to use in the winter, you'll need to add some insulation and a source for more heat than is needed to knock the chill off a June night.
The energy of light varies across the spectrum (blue light is more energetic than red) but only a certain amount of energy is needed to knock an electron free.
To further examine the roles of the miR-23-27 miR-23-27 miR-23-27l apoptosis in adults, it is needed to knoclustersr knonk downeuronalpression of the miR-23-27 clusters in future studies.
In addition, interventions are needed to support distressed families and prevent knock-on negative outcomes through programmes such as home visiting, and protection and enhancement of children's potential through early child development efforts.
Lastly, interventions are needed to support distressed families and prevent knock-on negative outcomes through programmes such as home visiting, and protection and enhancement of children's potential through early child development efforts.
Gene knock-out studies are needed to determine the extent to which each of the TSE-associated alterations in gene expression contributes to PrPsc formation, and disease pathogenesis and progression.
And then it was learned BMW needed to knock 1 to 3 m.p.g. off the original mileage ratings of some 3 Series models.
He said more research was needed to understand the knock-on effects for creatures from the changes in vegetation inadvertently caused by emissions from cars, industry and farms.
