Complex sentence: Aitape had been occupied by the Japanese in 1942 and then recaptured by an American landing on 22 April 1944, it was developed as a base area to support the continuing drive towards the Philippines.
Split into simpler sentences: Aitape had been occupied by the Japanese in 1942 and then recaptured by an American landing on 22 April 1944. It was developed as a base area to support the continuing drive towards the Philippines.