TASK DEFINITION: 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'.
PROBLEM: Sentence 1:The fluid pumping efficiency of a valveless system , however , is not necessarily lower than that having valves . Sentence 2:In fact , many fluid - dynamical systems in nature and engineering more or less rely upon valveless pumping to transport the working fluids therein .

SOLUTION: PAIR_CONN

PROBLEM: Sentence 1:Working at the ' home front ' during The Blitz , she spent many nights moving very ill children and babies from their beds to safer underground shelters . Sentence 2:nan

SOLUTION: SINGLE_CATAPHORA

PROBLEM: Sentence 1:Plus people can be especially emotional when it comes to their animals because they may have a strong connection to the animal . Sentence 2:nan

SOLUTION:
SINGLE_CONN_INNER_ANAPHORA