These quotations were effective in sending complex messages to his friends, because, in his day, people could quote from such authors with every expectation of being understood

The problem quoted isn't one, but there are problems in the reading section that ask you to distinguish relative pronouns from relative adverbs

My father achieved that and more in four words, which made quoting Shakespeare as effective as any business adviser could wish

The data cited in King's research is taken from UNESCO's 1970 white paper on world population

He has extracted a great many examples from the grammar book

We wish to quote a part of your paper in our new catalogue

From the menu-bar's "Reply" select "create follow-up message". The message you reply to is quoted