Complex sentence: The bases stick out from the pentose-phosphate polymer backbone in DNA and are hydrogen bonded in pairs to their complementary partner (A with T and G with C) creating a double helix with pentose phosphate backbones on either side thus forming a secondary structure.
Split into simpler sentences: The bases stick out from the pentose-phosphate polymer backbone in DNA and are hydrogen bonded in pairs to their complementary partners (A with T and G with C). This creates a double helix with pentose phosphate backbones on either side, thus forming a secondary structure.