diff --git a/refs.md b/refs.md
new file mode 100644
index 0000000..2831c5d
--- /dev/null
+++ b/refs.md
@@ -0,0 +1,4 @@
+1. https://github.com/vinodotdev/node-to-rust
+2. https://doc.rust-lang.org/stable/rust-by-example/primitives.html
+3. https://github.com/dtolnay/rust-quiz
+4. 
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diff --git a/src/SUMMARY.md b/src/SUMMARY.md
index 67c21db..602bdc8 100644
--- a/src/SUMMARY.md
+++ b/src/SUMMARY.md
@@ -1,4 +1,11 @@
 # Summary
 
 - [Lifetime](lifetime/intro.md)
-  - [&'static and T: 'static](lifetime/static.md)
\ No newline at end of file
+  - [basic](lifetime/basic.md)
+  - [&'static and T: 'static](lifetime/static.md)
+
+- [Tests](tests/intro.md)
+  - [Benchmark](tests/benchmark.md)
+
+- [Functional Programming](functional-programming/intro.md)
+  - [Closure](functional-programming/closure.md)
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diff --git a/src/functional-programming/closure.md b/src/functional-programming/closure.md
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index 0000000..fb73740
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+++ b/src/functional-programming/closure.md
@@ -0,0 +1,51 @@
+# Closure
+
+下面代码是Rust圣经课程中[闭包](http://course.rs/advance/functional-programing/closure.html#结构体中的闭包)章节的课内练习题答案：
+
+```rust
+struct Cacher<T,E>
+where
+    T: Fn(E) -> E,
+    E: Copy
+{
+    query: T,
+    value: Option<E>,
+}
+
+impl<T,E> Cacher<T,E>
+where
+    T: Fn(E) -> E,
+    E: Copy
+{
+    fn new(query: T) -> Cacher<T,E> {
+        Cacher {
+            query,
+            value: None,
+        }
+    }
+
+    fn value(&mut self, arg: E) -> E {
+        match self.value {
+            Some(v) => v,
+            None => {
+                let v = (self.query)(arg);
+                self.value = Some(v);
+                v
+            }
+        }
+    }
+}
+fn main() {
+  
+}
+
+#[test]
+fn call_with_different_values() {
+    let mut c = Cacher::new(|a| a);
+
+    let v1 = c.value(1);
+    let v2 = c.value(2);
+
+    assert_eq!(v2, 1);
+}
+```
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diff --git a/src/functional-programming/intro.md b/src/functional-programming/intro.md
new file mode 100644
index 0000000..dca041e
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+++ b/src/functional-programming/intro.md
@@ -0,0 +1 @@
+# Functional Programming
diff --git a/src/lifetime/basic.md b/src/lifetime/basic.md
new file mode 100644
index 0000000..40439f4
--- /dev/null
+++ b/src/lifetime/basic.md
@@ -0,0 +1,26 @@
+## 生命周期消除
+
+```rust
+fn print(s: &str);                                      // elided
+fn print<'a>(s: &'a str);                               // expanded
+
+fn debug(lvl: usize, s: &str);                          // elided
+fn debug<'a>(lvl: usize, s: &'a str);                   // expanded
+
+fn substr(s: &str, until: usize) -> &str;               // elided
+fn substr<'a>(s: &'a str, until: usize) -> &'a str;     // expanded
+
+fn get_str() -> &str;                                   // ILLEGAL
+
+fn frob(s: &str, t: &str) -> &str;                      // ILLEGAL
+
+fn get_mut(&mut self) -> &mut T;                        // elided
+fn get_mut<'a>(&'a mut self) -> &'a mut T;              // expanded
+
+fn args<T: ToCStr>(&mut self, args: &[T]) -> &mut Command                  // elided
+fn args<'a, 'b, T: ToCStr>(&'a mut self, args: &'b [T]) -> &'a mut Command // expanded
+
+fn new(buf: &mut [u8]) -> BufWriter;                    // elided
+fn new(buf: &mut [u8]) -> BufWriter<'_>;                // elided (with `rust_2018_idioms`)
+fn new<'a>(buf: &'a mut [u8]) -> BufWriter<'a>          // expanded
+```
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diff --git a/src/tests/benchmark.md b/src/tests/benchmark.md
new file mode 100644
index 0000000..f883201
--- /dev/null
+++ b/src/tests/benchmark.md
@@ -0,0 +1,3 @@
+# Benchmark
+
+https://doc.rust-lang.org/unstable-book/library-features/test.html
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diff --git a/src/tests/intro.md b/src/tests/intro.md
new file mode 100644
index 0000000..007eb95
--- /dev/null
+++ b/src/tests/intro.md
@@ -0,0 +1 @@
+# Tests