我真的是服了

这个是所谓的二级标题？

能插入链接不我也不太清楚，测试一下，戳我

测试一下图片咯

测试一下音频插入～

测试一下视频插入

测试一下代码插入：

import numpy as np
import matplotlib.pyplot as plt

# Define the Hubble constant H_0 in km/s/Mpc
H_0 = 70.0
# Define the matter density parameter Omega_m
Omega_m = 0.3
# Define the dark energy density parameter Omega_lambda
Omega_lambda = 0.7

# Calculate the dimensionless Hubble parameter E(z)
def E(z):
    return np.sqrt(Omega_m * (1 + z)**3 + Omega_lambda)

# Calculate the growth factor D(z) as a function of redshift z
def D_growth(z):
    # Initialize the array for D(z)
    D = np.zeros(len(z))
    # Set the initial condition for D(z) at z=0
    D[0] = 1.0
    # Calculate D(z) at other redshifts using the differential equation
    for i in range(1, len(z)):
        dDdz = (3.0 / (1 + z[i]) / E(z[i])) * D[i - 1]
        D[i] = D[i - 1] + dDdz * (z[i] - z[i - 1])
    return D

# Define the range of redshift z
z = np.linspace(0, 2, 100)
# Calculate the growth factor D(z) as a function of redshift z
D = D_growth(z)

# Plot the growth factor D(z) as a function of redshift z
plt.plot(z, D)
plt.xlabel("Redshift z")
plt.ylabel("Growth factor D(z)")
plt.show()