气球: balloon...
跟不上: not able to keep up with...
如愿以偿: to have one's wish fulfilled...
改变: to change, to alter, to transform...
敏捷: nimble, quick, shrewd...
盛产: to produce in abundance, to be rich in...
审视: to look closely at, to examine...
症状: symptom (of an illness)...
字眼: wording...
夏季: summer...