(3) The performance of mLSTM with bi-LSTM sentence modeling compared with the model with standard LSTM sentence modeling when d is set to 150 shows that using bi-LSTM to process the original sentences helps  (86.0% vs. 85.7% on the test data), but the difference is small and the complexity of bi-LSTM is much higher than LSTM.
when we increased d to 300 we did not experiment with bi-LSTM sentence modeling.