1. dig in

1. You''d better dig in at once.
    你最好马上去做。

2. We should dig those young trees in a bit deeper.
    我们应该把小树埋得深一些。

1. 掘土以参进(肥料等)：dig down 挖下去;掘倒 | dig in 掘土以参进(肥料等) | dig out 掘出;挖掉

2. 挖地：Death grip 握杆僵硬(过度用力握住球杆) | Dig in 挖地 | Digging 杆头击中地面

3. 掘土以掺进：dig down 挖下 | dig in 掘土以掺进 | dig into 钻研

4. 掘进;插入;钻头切入岩层：dig a pit 挖池 | dig in 掘进;插入;钻头切入岩层 | dig 挖掘;出土物;刺戳;掘

1. 翻土掺进;把…混入（土里）
    If you dig a substance in, or dig it into the soil, you mix it into the soil by digging.

dig in的解释

    e.g. I usually dig in a small barrow load of compost in late summer...
           夏末时节，我通常会把一小车堆肥施到土里。
    e.g. To dig calcium into the soil, he warned, does not help the plant.
           他告诫说，翻土掺钙并不利于植物生长。

2. (士兵)挖掩体隐蔽，掘壕防守
    When soldiers dig in or dig themselves in, they dig trenches and prepare themselves for an attack by the enemy.

    e.g. The battalion went directly to the airport to begin digging in...
           该营直接开到机场掘壕防守。
    e.g. The enemy must be digging themselves in now ready for the attack...
           敌人现在一定在挖掩体，准备迎接进攻。

3. （面临失败、困境等时）固执己见，坚定立场，坚持不懈
    If you say that someone is digging in, you mean that they are not changing their mind or weakening their efforts, although they may be losing a contest or facing difficult problems.

dig in

    e.g. A yawning North-South gulf has opened up with both sides digging in.
           双方都坚持自己的立场，南北之间出现了一条鸿沟。

4. 开始大吃;开始尽情吃
    If someone digs in, or digs into some food, they start eating eagerly. If you tell someone to dig in, you are inviting them to start eating, and encouraging them to eat as much as they want.

    e.g. ''Listen,'' said Daisy, digging into her oatmeal...
           “听着，”黛西一边大口喝着燕麦粥一边说道。
    e.g. Pull up a chair and dig in!
           拉把椅子过来开吃吧！

1. eat heartily

    e.g. The food was placed on the table and the children pitched in

    Synonym: pitch in

2. occupy a trench or secured area

    e.g. The troops dug in for the night

    Synonym: entrench