diff --git a/16_day/bootpack.c b/16_day/bootpack.c
index 2d41a06..190a247 100644
--- a/16_day/bootpack.c
+++ b/16_day/bootpack.c
@@ -75,7 +75,7 @@ void HariMain(void)
 		task_b[i]->tss.fs = 1 * 8;
 		task_b[i]->tss.gs = 1 * 8;
 		*((int *) (task_b[i]->tss.esp + 4)) = (int) sht_win_b[i];
-		task_run(task_b[i]);
+		task_run(task_b[i], i + 1);
 	}
 
 	/* sht_win */
diff --git a/16_day/bootpack.h b/16_day/bootpack.h
index 8a42a78..e518272 100644
--- a/16_day/bootpack.h
+++ b/16_day/bootpack.h
@@ -196,6 +196,7 @@ struct TSS32 {
 };
 struct TASK {
 	int sel, flags;		/* sel用来存放GDT的编号*/
+	int priority; /* 优先级 */
 	struct TSS32 tss;
 };
 struct TASKCTL {
@@ -207,6 +208,6 @@ struct TASKCTL {
 extern struct TIMER *task_timer;
 struct TASK *task_init(struct MEMMAN *memman);
 struct TASK *task_alloc(void);
-void task_run(struct TASK *task);
+void task_run(struct TASK *task, int priority);
 void task_switch(void);
 void task_sleep(struct TASK *task);
diff --git a/16_day/fifo.c b/16_day/fifo.c
index 12beeb5..0c51e4c 100644
--- a/16_day/fifo.c
+++ b/16_day/fifo.c
@@ -18,7 +18,7 @@ void fifo32_init(struct FIFO32 *fifo, int size, int *buf, struct TASK *task)
 }
 
 int fifo32_put(struct FIFO32 *fifo, int data)
-/*给FIFO发送数据并储存在FIFO中*/
+/*向FIFO写入数据并累积起来*/
 {
 	if (fifo->free == 0) {
 		/*没有空余空间，溢出*/
@@ -33,7 +33,7 @@ int fifo32_put(struct FIFO32 *fifo, int data)
 	fifo->free--;
 	if (fifo->task != 0) {
 		if (fifo->task->flags != 2) { /*如果任务处于休眠状态*/
-			task_run(fifo->task); /*将任务唤醒*/
+			task_run(fifo->task, 0); /*将任务唤醒*/
 		}
 	}
 	return 0;
diff --git a/16_day/mtask.c b/16_day/mtask.c
index ac996b3..8fe0221 100644
--- a/16_day/mtask.c
+++ b/16_day/mtask.c
@@ -20,12 +20,13 @@ struct TASK *task_init(struct MEMMAN *memman)
 
 	task = task_alloc();
 	task->flags = 2; /*活动中标志*/
+	task->priority = 2; /* 0.02秒 */
 	taskctl->running = 1;
 	taskctl->now = 0;
 	taskctl->tasks[0] = task;
 	load_tr(task->sel);
 	task_timer = timer_alloc();
-	timer_settime(task_timer, 2);
+	timer_settime(task_timer, task->priority);
 	return task;
 }
 
@@ -57,23 +58,29 @@ struct TASK *task_alloc(void)
 	return 0; /*全部正在使用*/
 }
 
-void task_run(struct TASK *task)
+void task_run(struct TASK *task, int priority)
 {
-	task->flags = 2; /*活动中标志*/
-	taskctl->tasks[taskctl->running] = task;
-	taskctl->running++;
+	if (priority > 0) {
+		task->priority = priority;
+	}
+	if (task->flags != 2) {
+		task->flags = 2; /*活动中标志*/
+		taskctl->tasks[taskctl->running] = task;
+		taskctl->running++;
+	}
 	return;
 }
 
-void task_switch(void)
-{
-	timer_settime(task_timer, 2);
+void task_switch(void){
+	struct TASK *task;
+	taskctl->now++;
+	if (taskctl->now == taskctl->running) {
+		taskctl->now = 0;
+	}
+	task = taskctl->tasks[taskctl->now];
+	timer_settime(task_timer, task->priority);
 	if (taskctl->running >= 2) {
-		taskctl->now++;
-		if (taskctl->now == taskctl->running) {
-			taskctl->now = 0;
-		}
-		farjmp(0, taskctl->tasks[taskctl->now]->sel);
+		farjmp(0, task->sel);
 	}
 	return;
 }