24 Commonwealth v. O'Neil, 67 Mass. App. Ct. 284, 294 (2006) (defendant's letters and telephone calls seriously alarmed victim who felt "concern[ed]" and "very scared," and asked State officials for assistance). Here, the Lyons family did not merely experience uneasiness associated with day-to-day living, but rather, as the ominous and hostile acts perpetrated by the defendants continued to escalate, the totality of the situation evoked the type of "serious negative emotional experience" required under the statute. Kessler, supra at 774. As for whether serious alarm must be shown for each individual act or may be measured cumulatively, we conclude that the statute's wording ties the requirement to the over-all pattern of conduct. The statutory language of § 43A (a) requires that the "pattern of conduct" or "series of acts" "seriously alarms." As a general rule of statutory construction, "words importing the plural number may include the singular." G. L. c. 4, § 6, Fourth. Accordingly, "acts" might refer to a single act as well as multiple acts. However, the rules of grammar and proper subject-verb agreement instruct a reading of "alarms" to modify the singular noun of one "pattern" or one "series," rather than the noun "acts."13 13 The evidence at Other States have also held that in similar criminal statutes where the actus reus of the crime is defined as a "series of acts," each act need not induce fear. See, e.g.,