Complex sentence: BMW Sauber's Nick Heidfeld was quickest on the second day, with Massa spinning off in the gravel at the Ascari chicane, causing testing to be halted for a short period of time.
Split into simpler sentences: BMW Sauber's Nick Heidfeld was quickest on the second day. Massa spun off into the gravel at the Ascari chicane, causing testing to be halted for a short period of time.