Which sentence contains an infinitive? li says learning to speak french is easier than you think. marco went to his doctor for advice about his knee. mrs. wilson sent the letters and packages to charlie. if she hurries, lillian will be there by quarter to four.

A) Li says learning to speak French is easier than you think.

Explanation: an infinitive is the basic form of a verb, without an inflection binding it to a particular subject or tense. It is form by the particle "to" plus a verb. From the given options, the sentence that contains an infinitive, is the corresponding to option A, in the phrase "to speak" ("to" plus a verb). In the other sentences the word "to" is acting as a preposition ("to his doctor," "to Charlie," and "to four").