Another common error made by non-native English speakers (and native English speakers!) is the use of “which” and “that”.
- The pH values of soil samples, which were obtained at night, ranged from 4.1 to 6.5.
- The pH values of soil samples that were obtained at night ranged from 4.1 to 6.5.
These sentences are not the same.
1. The pH values of soil samples, which were obtained at night, ranged from 4.1 to 6.5.
↑
This clause is simply additional information and not essential to the meaning of the sentence. If we change (or remove) the clause, the overall meaning does not change.
The pH values of soil samples, which were obtained during the day, ranged from 4.1 to 6.5.
The pH values of soil samples ranged from 4.1 to 6.5.
This is known as a nonrestrictive clause. (Note the commas surrounding the clause, indicating the information is non-essential, similar to parenthesis).
2. The pH values of soil samples that were obtained at night ranged from 4.1 to 6.5.
↑
This adjective clause describes the type of soil sample that was measured and so is essential to the meaning of the sentence. If we change (or remove) the clause, the meaning of the sentence changes.
The pH values of soil samples that were obtained during the day ranged from 3.9 to 7.1.
This is known as a restrictive clause. (Note that no commas are surrounding the clause, indicating that the information is essential, not extra.)
Enter the correct pronoun (which or that) into the blank spaces below.
- The results, _____ are shown in Tables 1 and 2, agree very closely with those obtained by Smith (1999).
2. Type-1 diabetes _____ is slow to develop was not an issue in our trial.
3. This randomized study included patients with a pathologic diagnosis of pancreas cancer ____ was locally advanced or metastatic.
4. The dFdCTP competes with deoxycytidine triphosphate (dCTP) for incorporation into DNA, ____ in turn inhibits DNA synthesis.
1. The results, which are shown in Tables 1 and 2, agree very closely with those obtained by Smith (1999).
This clause is simply additional information and not essential to the meaning of the sentence. If we remove the clause, the meaning is unchanged.
The results agree very closely with those obtained by Smith (1999). [Meaning unchanged]
2. Type-1 diabetes that is slow to develop was not an issue in our trial.
The adjective clause is essential to the meaning of the sentence. Only a particular type of type-1 diabetes was not an issue in the trial, not other types. If we remove the clause, the meaning changes.
Type-1 diabetes was not an issue in our trial. [Meaning changed]
3. This randomized study included patients with a pathologic diagnosis of pancreas cancer that was locally advanced or metastatic.
Again, the adjective clause is essential to the meaning of the sentence. Only patients with particular types of pancreas cancer (those that were locally advanced or metastatic) were included in the study. If we remove the clause, the meaning changes.
This randomized study included patients with a pathologic diagnosis of pancreas cancer. [Meaning changed]
4. The dFdCTP competes with deoxycytidine triphosphate (dCTP) for incorporation into DNA, which in turn inhibits DNA synthesis.
This clause is simply additional information and not essential to the meaning of the sentence. If we remove the clause, the meaning is unchanged.
The dFdCTP competes with deoxycytidine triphosphate (dCTP) for incorporation into DNA. [Meaning unchanged]
