diff --git a/alpha_automl/resource/base_grammar.bnf b/alpha_automl/resource/base_grammar.bnf
index 3736436..a1b6d25 100644
--- a/alpha_automl/resource/base_grammar.bnf
+++ b/alpha_automl/resource/base_grammar.bnf
@@ -1,6 +1,6 @@
 S -> CLASSIFICATION_TASK | REGRESSION_TASK | CLUSTERING_TASK | TIME_SERIES_FORECAST_TASK | SEMISUPERVISED_TASK | NA_TASK
 CLASSIFICATION_TASK -> IMPUTER ENCODERS FEATURE_GENERATOR FEATURE_SCALER FEATURE_SELECTOR CLASSIFIER
-REGRESSION_TASK -> IMPUTER ENCODERS FEATURE_GENERATOR FEATURE_SCALER FEATURE_SELECTOR REGRESSOR REGRESSION_ENSEMBLER
+REGRESSION_TASK -> IMPUTER ENCODERS FEATURE_GENERATOR FEATURE_SCALER FEATURE_SELECTOR REGRESSOR
 CLUSTERING_TASK -> IMPUTER ENCODERS FEATURE_GENERATOR FEATURE_SCALER FEATURE_SELECTOR CLUSTERER
 TIME_SERIES_FORECAST_TASK -> IMPUTER TIME_SERIES_FORECASTER | REGRESSION_TASK
 SEMISUPERVISED_TASK -> IMPUTER ENCODERS FEATURE_GENERATOR FEATURE_SCALER SEMISUPERVISED_CLASSIFIER