In this task, you are given two sentences in the English language and your task is to classify them into one of their discourse types. A discourse type is an indicator to classify the given two sentences on the basis of a co-text as well as a relevant context. There are 13 discourse types in total which are 'SINGLE_S_COORD', 'SINGLE_CATAPHORA', 'SINGLE_CONN_INNER', 'SINGLE_APPOSITION', 'SINGLE_VP_COORD', 'SINGLE_CONN_START', 'PAIR_ANAPHORA', 'PAIR_CONN', 'SINGLE_RELATIVE', 'SINGLE_CONN_INNER_ANAPHORA', 'SINGLE_S_COORD_ANAPHORA', 'PAIR_CONN_ANAPHORA' and 'PAIR_NONE'.

Sentence 1:Galvanized steel offers more protection from rust , so this is usually used when the gusset plate is exposed to the elements . Sentence 2:nan
SINGLE_S_COORD

Sentence 1:Doctor Sun was born in Peking , People 's Republic of China , and was working as a scientist during the Cultural Revolution . Sentence 2:nan
SINGLE_APPOSITION

Sentence 1:Lang is forlorn but is unable to convince her to stay . Sentence 2:nan

SINGLE_S_COORD