Two words combination in Python

sentence = input('Enter sentence: ')
sentence = sentence.split(' ')
all_comb = []
for i in range(len(sentence)-2):
    for j in range(i+2, len(sentence)):
        all_comb.append([sentence[i], sentence[j]])
all_comb = sorted(all_comb, key=lambda x: (x[0]))
for i in range(len(all_comb)):
    for j in range(2):
        for k in range(1, len(sentence)-1):
            try:
                if all_comb[i][j]==sentence[k]:
                    try:
                        if all_comb[i][j+1]==sentence[k+1]:
                            all_comb.pop(k)
                    except:
                        a=1
                    try:
                        if all_comb[i][j+1]==sentence[k-1]:
                            all_comb.pop(k)
                    except:
                        a=1
                    
                    try:
                        if all_comb[i][j-1]==sentence[k+1]:
                            all_comb.pop(k)
                    except:
                        a=1
                    try:
                        if all_comb[i][j-1]==sentence[k-1]:
                            all_comb.pop(k)
                    except:
                        a=1
            except:
                a=1
print(all_comb)