＝AだけでなくBもまた
強意で動詞を修飾する not only（否定語句）が文頭にくると 倒置 が生じます（疑問文の形になります）。
Not only is(V) the beagle explorer(S) floating(V) in the Macy's Thanksgiving parade, (but) he's also the zero-gravity indicator on our Artemis I mission currently flying around the Moon.
