Only she tasted the rutabaga means that no one else did. She tasted only the rutabaga means that she tasted nothing else. She only tasted the rutabaga means that she did not devour the rutabaga; she merely nibbled at it.
By Philip B. Corbett / New York Times
In fluid writing, the best place for the time element is after the verb — immediately after, if the verb has no direct object: The dean of Cordero University announced on Tuesday that undergraduates would be required to perform four hours of community service a week. But if there is a direct object, the object should immediately follow the verb, and the time element should ideally follow both: Mayor Leslie T. Baranek ordered the police on Tuesday to arrest jaywalkers.
When the direct object is long or cumbersome, the time element must come before the verb, though smoothness will usually suffer: Mayor Leslie T. Baranek on Tuesday ordered the police, already complaining of overwork and threatening a slowdown, to arrest jaywalkers.
that / which (restrictive and nonrestrictive clauses). The standard rule requires that you use that only to introduce a restrictive (or defining) relative clause, which identifies the person or thing being talked about; in this use it should never be preceded by a comma. Thus, in the sentence The house that Jack built has been torn down, the clause that Jack built is a restrictive clause telling which specific house was torn down. Similarly, in I am looking for a book that is easy to read, the restrictive clause that is easy to read tells what kind of book is desired. 1
By contrast, you use which only with nonrestrictive (or nondefining) clauses, which give additional information about something that has already been identified in the context; in this use, which is always preceded by a comma. Thus you should say The students in Chemistry 101 have been complaining about the textbook, which (not that) is hard to follow. The clause which is hard to follow is nonrestrictive in that it does not indicate which text is being complained about; even if it were omitted, we would know that the phrase the textbook refers to the text in Chemistry 101. It should be easy to follow the rule in nonrestrictive clauses like this, since which here sounds more natural than that. 2
Some people extend the rule and insist that, just as that should be used only in restrictive clauses, which should be used only in nonrestrictive clauses. By this thinking, you should avoid using which in sentences such as I need a book which will tell me all about city gardening, where the restrictive clause which will tell me all about city gardening describes what sort of book is needed. But this use of which with restrictive clauses is very common, even in edited prose. If you fail to follow the rule in this point, you have plenty of company. Moreover, there are some situations in which which is preferable to that. Which can be especially useful where two or more relative clauses are joined by and or or: It is a philosophy in which ordinary people may find solace and which many have found reason to praise. You may also want to use which to introduce a restrictive clause when the preceding phrase contains a that: We want to assign only that book which will be most helpful. 3
omitting that. You can omit that in a relative clause when the subject of the clause is different from the word or phrase the clause refers to. Thus, you can say either the book that I was reading or the book I was reading. You can also omit that when it introduces a subordinate clause: I think we should try again. You should not omit that, however, when the subordinate clause begins with an adverbial phrase or anything other than the subject: She said that under no circumstances would she allow us to skip the meeting. The book argues that eventually the housing supply will increase. This last sentence would be ambiguous if that were omitted, since the adverb eventually could then be construed as modifying either argues or will increase. 4
that instead of who. The man that wanted to talk to you just called back. Some people say that you can only use who and not that to introduce a restrictive relative clause that identifies a person. But that has been used in this way for centuries. It is a quintessential English usage, going back to the Old English period, and has been used by our best writers. So it is entirely acceptable to write either the man that wanted to talk to you or the man who wanted to talk to you. 5