diff --git a/.gitignore b/.gitignore
index 790ab50ad8939a56606bf1b3019308bc097a5ff9..509e2a83bf88757838eae9767fc5be7737411f38 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,4 @@
 DEST/
 *.deb
+build/
+release/
diff --git a/meson.build b/meson.build
index bdb054620db66b2262cb193c382cf302fb1ecdcd..3b84d877cf204bc20fae6aa79d03793bd3b9b213 100644
--- a/meson.build
+++ b/meson.build
@@ -1,6 +1,6 @@
 # -*- mode: conf -*-
 project('zero-pinyin-service', ['c', 'cpp'],
-  version: '0.7.3',
+  version: '0.8.0',
   license: 'GPL',
   default_options: [
     'warning_level=2',
@@ -63,8 +63,8 @@ executable('zero-pinyin-service', src,
   dependencies: shared_dep,
   install: true, install_dir: '/home/sylecn/bin/sbin/')
 
-test('parse-pinyin',
-  executable('parse-pinyin',
+test('parse-pinyin-test',
+  executable('parse-pinyin-test',
     ['../PinyinParser.cc', 'parse-pinyin.cpp', 'parse-pinyin-test.cpp'],
     dependencies: shared_dep))
 test('zero-pinyin-service-test',
diff --git a/operational b/operational
index 9f6b38725a2a45de148e717c93fadca87286147c..dc79827f01fbcc441bca722d61ac35e62c13874a 100644
--- a/operational
+++ b/operational
@@ -1,6 +1,6 @@
 * COMMENT -*- mode: org -*-
 #+Date: 2019-04-05
-Time-stamp: <2019-08-31>
+Time-stamp: <2019-10-22>
 #+STARTUP: content
 * notes                                                               :entry:
 ** 2019-08-31 ibus-pinyin userdb inference notice.
@@ -52,6 +52,40 @@ shared between zero-pinyin and ibus-pinyin.
 * later                                                               :entry:
 * current                                                             :entry:
 ** 
+** 2019-10-22 handle a an o en etc differently. only match exactly the character.
+no fuzzy matching or incomplete pinyin matching.
+
+if shengmu is 0, always strict match it.
+do not allow omit shengmu in zero.
+
+ao men
+澳门
+e nuo
+婀娜
+
+- DONE use different FLAGS for them.
+  FLAGS doesn't affect pinyin parsing.
+  if flag support is to be added, just add it in appdata, as property.
+  then use the property when building SQL.
+- DONE test in bogon VM.
+- DONE git push
+- build on debian 9 and release deb. later.
+
+- problems
+  - result = parse_pinyin("an", 15, PINYIN_FUZZY_ALL);
+    this only return 1 result.
+    not an and ang.
+    why?
+
+  - maybe flag is not used when parsing pinyin string. only used when building
+    the SQL statement.
+
+    build_sql_for_n_pinyin()
+    build_where_clause(pylist, n);
+    yes. here. I should pass the flags around.
+
+  - 
+
 ** 2019-08-31 how to format C code? do it before git commit.
 see ~/c/gtk-im-module/, it uses myastyle-pre-commit-check in git pre-commit
 ~/bin/myastyle-pre-commit-check
diff --git a/parse-pinyin-test.cpp b/parse-pinyin-test.cpp
index 21b85e6c5cf032cfef809e6d4fc223fd116e0fef..b8ff10ef862c98bfb61c0600c33fe2703ae5388a 100644
--- a/parse-pinyin-test.cpp
+++ b/parse-pinyin-test.cpp
@@ -69,6 +69,32 @@ test_parse_pinyin_incomplete_pinyin()
 	g_list_free_full(result, g_free);
 }
 
+static void
+test_parse_pinyin_yunmu_only_pinyin()
+{
+	GList *result = NULL;
+	Pinyin *thispy = NULL;
+
+	result = parse_pinyin("a", 15, PINYIN_FLAGS_NONE);
+	print_parse_result(result);
+	g_assert_cmpint(g_list_length(result), ==, 1);
+
+	thispy = (Pinyin *) g_list_nth_data(result, 0);
+	g_assert_cmpint(thispy->shengmu_i, ==, 0);
+	g_assert_cmpint(thispy->yunmu_i, ==, 24);
+	g_assert_cmpint(thispy->length, ==, 1);
+
+	g_list_free_full(result, g_free);
+
+	// flag doesn't affect pinyin parsing.
+	// flags are only effective when building the SQL.
+	result = parse_pinyin("an", 15, PINYIN_FUZZY_ALL);
+	print_parse_result(result);
+	g_assert_cmpint(g_list_length(result), ==, 1);
+
+	g_list_free_full(result, g_free);
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -77,6 +103,8 @@ main(int argc, char *argv[])
 			test_parse_pinyin);
 	g_test_add_func("/zero/test_parse_pinyin incomplete pinyin",
 			test_parse_pinyin_incomplete_pinyin);
+	g_test_add_func("/zero/test_parse_pinyin yunmu only pinyin",
+			test_parse_pinyin_yunmu_only_pinyin);
 
 	return g_test_run();
 }
diff --git a/zero-pinyin-service.c b/zero-pinyin-service.c
index 0bb24f32ef31ff0f7d083774122fc5503c2dd3ad..ecd5fc7c4f9e738d1e5f41c172677df07b5ecce7 100644
--- a/zero-pinyin-service.c
+++ b/zero-pinyin-service.c
@@ -52,14 +52,14 @@ build_where_clause(GList *pylist,
 	for (guint i = 0; i < n; ++i) {
 		g_assert_nonnull(iter);
 		thispy = (Pinyin *) iter->data;
-		if (thispy->shengmu_i) {
-			if (G_LIKELY(first_condition_done)) {
-				g_string_append_printf(s, "AND s%u=%d ", i, thispy->shengmu_i);
-			} else {
-				g_string_append_printf(s, "s%u=%d ", i, thispy->shengmu_i);
-				first_condition_done = TRUE;
-			}
+		/* do not allow omit shengmu. always do strict match */
+		if (G_LIKELY(first_condition_done)) {
+			g_string_append_printf(s, "AND s%u=%d ", i, thispy->shengmu_i);
+		} else {
+			g_string_append_printf(s, "s%u=%d ", i, thispy->shengmu_i);
+			first_condition_done = TRUE;
 		}
+		/* allow omit yunmu, if 0 don't match on it */
 		if (thispy->yunmu_i) {
 			if (G_LIKELY(first_condition_done)) {
 				g_string_append_printf(s, "AND y%u=%d ", i, thispy->yunmu_i);
@@ -310,18 +310,7 @@ get_candidates(sqlite3 *db,
 	}
 	GList *pylist = NULL;
 	guint pylist_len = 0;
-	const guint FLAGS = (PINYIN_INCOMPLETE_PINYIN |
-			     PINYIN_FUZZY_C_CH |
-			     PINYIN_FUZZY_CH_C |
-			     PINYIN_FUZZY_Z_ZH |
-			     PINYIN_FUZZY_ZH_Z |
-			     PINYIN_FUZZY_S_SH |
-			     PINYIN_FUZZY_SH_S |
-			     PINYIN_FUZZY_IN_ING |
-			     PINYIN_FUZZY_ING_IN |
-			     PINYIN_CORRECT_ALL);
-
-	pylist = parse_pinyin(preedit_str, 15, FLAGS);
+	pylist = parse_pinyin(preedit_str, 15, PINYIN_FLAGS_NONE);
 	pylist_len = g_list_length(pylist);
 
 	guint group_size = pylist_len;