In what sentence has a shift verb tense

How does the author's purpose affect his or her text structure

Which is not covered under the common topic “relationship” a. causes and effects b. comparisons and contrasts c. contraries and contradictions d. antecedents and consequences

Why is it important to include a descriptive subject heading? it in sorting the topics. it the recipient see its importance. e-mail programs won’t allow e-mail to be sent without it. it keeps junk e-mail separate from important e-mail.